Access systems and methods for minimally invasive surgery

ABSTRACT

A device for retracting tissue provides access to a spinal location within a patient. The device includes an elongate body and a passage. The elongate body has a proximal portion and a distal portion. The elongate body defines a length between the proximal and distal portions along a longitudinal axis such that the distal portion can be positioned inside the patient adjacent the spinal location while the proximal portion is accessible. A transverse cross-section of the elongate body in the proximal portion has a first dimension that is longer than a second dimension. The first dimension is perpendicular to the second dimension. The passage extends through the elongate body between the proximal and distal portions. The elongate body is configured such that the proximal portion may be tilted with respect to the distal portion in a first direction generally aligned with the first dimension and in a second direction generally aligned with the second dimension.

PRIORITY INFORMATION

This application is based on and claims priority to U.S. ProvisionalPatent Applications Nos. 60/497,822 (filed Aug. 26, 2003), 60/497,763(filed Aug. 26, 2003), 60/514,559 (filed Oct. 24, 2003), 60/545,587(filed Feb. 18, 2004), 60/579,643 (filed Jun. 15, 2004), the entirecontents of all of which are hereby expressly incorporated by referenceherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application relates to surgical systems and assemblies that includean access device for minimally invasive surgery, and in particularrelates to systems and devices that provide access to a surgicallocation, e.g. adjacent a spine, for one or more instruments to performa procedure at the surgical location.

2. Description of the Related Art

Spinal surgery presents significant difficulties to the physicianattempting to reduce chronic back pain or correct spinal deformitieswithout introducing additional trauma due to the surgical procedureitself. In order to access the vertebrae to perform spinal procedures,the physician is typically required to make large incisions and cut orstrip muscle tissue surrounding the spine. In addition, care must betaken not to injure nerve tissue in the area. Consequently, traditionalsurgical procedures of this type carry high risks of scarring, pain,significant blood loss, and extended recovery times.

Apparatuses for performing minimally invasive techniques have beenproposed to reduce the trauma of posterior spinal surgery by reducingthe size of the incision and the degree of muscle stripping in order toaccess the vertebrae. One such apparatus provides a constant diametercannula that is made narrow in order to provide a small entry profile.As a result, the cannula provides minimal space for the physician toobserve the body structures and manipulate surgical instruments in orderto perform the required procedures. A narrow cannula is typicallyinsufficient to perform one level spinal fixation procedures, whichrequires visualization of two vertebrae and introduction of screws,rods, as well as other large spinal fixation devices.

SUMMARY OF THE INVENTION

Accordingly, there is a need in the art for systems and methods fortreating the spine that provide minimally invasive access to the spinesuch that a variety of procedures, and preferably the entire procedureor at least a substantial portion thereof, can be performed via a singleaccess device.

In one embodiment, a device is provided for accessing a surgicallocation within a patient. The device comprises an elongate body havingan outer surface and an inner surface. The inner surface defines apassage extending through the elongate body and through which multiplesurgical instruments can be inserted simultaneously to the surgicallocation. The elongate body is capable of having a configuration wheninserted within the patient wherein the cross-sectional area of thepassage at a first location is greater than the cross-sectional area ofthe passage at a second location. The first location is distal to thesecond location. The proximal portion of the device may be coupled with,e.g., supporting, a mount outside the body. The mount may include anindexing collar that rests on one section of the proximal portion.

Advantageously, in some embodiments the devices as described herein canallow for improved access to a surgical location, such as for performinga procedure on a spinal location. In one embodiment the device can havean expandable distal portion. In one embodiment, the device can have anexpandable proximal portion. Expandable portions of the device canprovide the operator with an enlarged passage to improve the field ofvision and/or the working space within the access device. Moreover, theenlarged passage can allow for multiple instruments to be placed in thepassage, with the ability to articulate the instruments at desiredangles to reach desired locations in the working space.

In one embodiment a device for retracting tissue provides access to aspinal location within a patient. The device has an elongate body thathas a proximal end and a distal end. The elongate body has a lengthbetween the proximal and distal ends such that the distal end can bepositioned inside the patient adjacent the spinal location. The elongatebody has a generally oval shaped proximal portion and an expandabledistal portion. A passage extends through the elongate body between theproximal and distal ends. The passage is defined by a smooth metal innersurface extending substantially entirely around the perimeter of thepassage between the proximal and distal ends. The elongate body isexpandable between a first configuration sized for insertion into thepatient and a second configuration wherein the cross-sectional area ofthe passage at the distal end is greater than the cross-sectional areaof the passage at the proximal end.

In another embodiment, a device provides access to a surgical locationwithin a patient. The device has an elongate body that has a proximalend, a distal end, and an inner surface. The inner surface defines apassage that extends through the elongate body. Surgical instruments canbe inserted through the passage to the surgical location. The elongatebody is capable of having a configuration when located within thepatient wherein the cross-sectional area of the passage at a firstlocation is greater than the cross-sectional area of the passage at asecond location. The first location is distal to the second location.The passage is capable of having an oblong shaped cross section betweenthe second location and the proximal end.

In another embodiment, a device provides access to a surgical locationwithin a patient. The device has an elongate body that has a proximalend, a distal end, and an inner surface. The inner surface defines apassage that extends through the elongate body. Surgical instruments canbe inserted through the passage to the surgical location. The elongatebody is expandable from a first configuration to a second configurationwhen located within the patient. In the second configuration thecross-sectional area of the passage at a first location is greater thanthe cross-sectional area of the passage at a second location. The firstlocation is distal to the second location. The passage is capable ofhaving a generally oval shaped cross section between the second locationand the proximal end.

In another embodiment, a device provides access to a surgical locationwithin a patient. The device has an elongate body that has a proximalend, a distal end, and an inner surface. The inner surface defines apassage that extends through the elongate body. Surgical instruments canbe inserted through the passage to the surgical location. The elongatebody is capable of having a configuration when inserted within thepatient wherein the cross-sectional area of the passage at a firstlocation is greater than the cross-sectional area of the passage at asecond location. The first location is distal to the second location.The passage is capable of having a cross section between the secondlocation and the proximal end. The cross section is defined by first andsecond generally parallel opposing side portions and first and secondgenerally arcuate opposing side portions.

In another embodiment, a method for accessing a surgical location withina patient comprises providing a device that has an elongate body. Theelongate body has a proximal end, a distal end, and an inner surface.The inner surface defines a passage extending through the elongate body.Surgical instruments can be inserted through the passage to the surgicallocation. The passage is capable of having an oblong shaped crosssection between the second location and the proximal end. The elongatebody has an expanded configuration. The elongate body is configured forinsertion into the patient. The device is inserted into the patient tothe surgical location. The device is expanded to the expandedconfiguration.

In another embodiment, a device provides access to a surgical locationwithin a patient. The device has an elongate body that has a proximalend, a distal end, and an inner surface. The inner surface defines apassage that extends through the elongate body. Surgical instruments canbe inserted through the passage to the surgical location. The elongatebody is capable of having a configuration when located within thepatient wherein the cross-sectional area of the passage at a firstlocation is greater than the cross-sectional area of the passage at asecond location. The first location is distal to the second location. Alighting element is coupled with the elongate body to provide light tothe surgical location.

In another embodiment, a method for providing access to a spinallocation within a patient, comprises providing an elongate body having aproximal portion, a distal portion, a passage extending therethrough,and a locking element. The proximal portion is positioned at leastpartially outside the patient and the distal portion is positioned atleast partially inside the patient adjacent the spinal location. Theelongate body is actuated from a contracted configuration to an expandedconfiguration. The locking element is manipulated to retain the elongatebody in the expanded configuration.

In another embodiment, a device for providing access to a surgicallocation within a patient comprises an elongate body having a proximalportion, a distal portion, a first slot segment, and a second slotsegment that is angled relative to said first slot segment. The elongatebody defines a passage for accessing the surgical location with surgicalinstruments. The elongate body has a contracted configuration forinsertion into the patient and an expanded configuration for providingaccess to the surgical location. The cross-sectional area of the passageat a first location of the elongate body is greater than thecross-sectional area of said passage at a second location of theelongate body. A movable tab is configured to extend into the secondslot segment when the elongate body is in the expanded configuration toretain the elongate body in the expanded configuration.

In another embodiment, a device for providing access to a surgicallocation within a patient comprises an elongate body having a proximalportion, a distal portion, and an inner surface defining a passageextending through the elongate body. The passage is capable of providingaccess for surgical instruments to be inserted to the surgical location.The elongate body is capable of having a configuration wherein thecross-sectional area of the passage at a first location is greater thanthe cross-sectional area of said passage at a second location. The firstlocation is distal to the second location. A lock is coupled with theelongate body. The lock is actuatable to maintain the elongate body inthe configuration.

In another embodiment, a device for providing access to a surgicallocation within a patient comprises an elongate body having a proximalportion, a distal portion coupled with the proximal portion, and aninner surface defining a passage extending through the elongate body andthrough which surgical instruments can be inserted to the surgicallocation. The elongate body is expandable from a contractedconfiguration to an expanded configuration wherein the cross-sectionalarea of the passage at a first location in the distal portion is greaterthan the cross-sectional area of the passage at a second location in theproximal portion. The passage has an oblong shaped cross-section at thesecond location. The elongate body is capable of resisting actuationfrom the expanded configuration to the contracted configuration whendeployed.

In another embodiment, a retractor is provided that has an elongate bodyand an expandable shroud. The elongate body has an outer surface and aninner surface partially defining a passage. The elongate body also has afirst longitudinal edge and a second longitudinal edge. The elongatebody is capable of having an enlarged configuration when inserted withinthe patient. In the enlarged configuration the first longitudinal edgeis spaced apart from the second longitudinal edge. The expandable shroudis configured to extend from the first longitudinal edge to the secondlongitudinal edge when the first and second edges are spaced apart. Theshroud partially defines the passage. The cross-sectional area of saidpassage at a first location is greater than the cross-sectional area ofthe passage at a second location, wherein the first location is distalto the second location.

In another embodiment, a method provides access to a surgical locationwithin a patient. A retractor is provided for insertion into thepatient. The retractor has an elongate body that has an outer surface,an inner surface partially defining a passage, a first longitudinaledge, and a second longitudinal edge. The retractor also has anexpandable shroud that extends from the first longitudinal edge to thesecond longitudinal edge. The retractor is positioned in a low-profileconfiguration for insertion into the patient. In the low-profileconfiguration, the first longitudinal edge is adjacent the secondlongitudinal edge. The retractor is positioned in an enlargedconfiguration wherein the cross-sectional area of the passage at a firstlocation is greater than the cross-sectional area of said passage at asecond location, wherein the first location is distal to the secondlocation. The shroud is expanded to cover a gap formed between the firstand second longitudinal edges.

In another embodiment, a device for retracting tissue provides access toa spinal location within a patient. The device includes an elongate bodyand a passage. The elongate body has a proximal portion and a distalportion. The elongate body defines a length between the proximal anddistal portions along a longitudinal axis such that the distal portioncan be positioned inside the patient adjacent the spinal location whilethe proximal portion is accessible. A transverse cross-section of theelongate body in the proximal portion has a first dimension that islonger than a second dimension. The first dimension is perpendicular tothe second dimension. The passage extends through the elongate bodybetween the proximal and distal portions. The elongate body isconfigured such that the proximal portion may be tilted with respect tothe distal portion in a first direction generally aligned with the firstdimension and in a second direction generally aligned with the seconddimension.

In another embodiment, a device for retracting tissue provides access toa spinal location within a patient. The device includes a proximalportion, a distal portion, a first joint, and a second joint. Theproximal portion partially defines a passage through which surgicalinstruments can be inserted to the surgical location. The distal portionpartially defines the passage. The first joint is located on a firstside of the device. The second joint is located on a second side of thedevice opposite the first joint. The proximal portion is capable ofbeing positioned with respect to the distal portion about a first axisextending through the first and second joints and about a second axisthat is perpendicular to the first axis.

In another embodiment, a method of accessing a surgical location withina patient is provided. A retractor that has a proximal portion, a distalportion, and a passage extending therethrough is provided. At least oneof the proximal and distal portions is configured such that the portionhas a first dimension and a second dimension, the first dimension beinglonger than and perpendicular to the second dimension. The elongate bodyis configured such that the proximal portion may be tilted with respectto the distal portion in a first direction generally aligned with thefirst dimension and in a second direction generally aligned with thesecond dimension. The retractor is advanced into the patient until thedistal portion is adjacent a spinal location.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the invention will becomeapparent from the following detailed description taken in conjunctionwith the accompanying figures showing illustrative embodiments of theinvention, in which:

FIG. 1 is a perspective view of one embodiment of a surgical system andone embodiment of a method for treating the spine of a patient.

FIG. 2 is a perspective view of one embodiment of an access device in areduced profile configuration.

FIG. 3 is a perspective view of the access device of FIG. 2 in a firstenlarged configuration.

FIG. 4 is a perspective view of the access device of FIG. 2 in a secondenlarged configuration.

FIG. 5 is a view of one embodiment of a skirt portion of an accessdevice.

FIG. 6 is a view of another embodiment of a skirt portion of an accessdevice.

FIG. 7 is a perspective view of another embodiment of an access devicein an enlarged configuration.

FIG. 8 is an enlarged sectional view of the access device of FIG. 7taken along lines 8-8 of FIG. 7.

FIG. 9 is a sectional view of the access device of FIG. 7 taken alonglines 9-9 of FIG. 7.

FIG. 10 is a perspective view of another embodiment of an access devicein an enlarged configuration.

FIG. 11 is an enlarged sectional view of the access device of FIG. 10taken along lines 11-11 of FIG. 10.

FIG. 12 is a sectional view of the access device of FIG. 10 taken alonglines 12-12 of FIG. 10.

FIG. 13 is a view of a portion of another embodiment of the accessdevice.

FIG. 14 is a view of a portion of another embodiment of the accessdevice.

FIG. 15 is a sectional view illustrating one embodiment of a stage ofone embodiment of a method for treating the spine of a patient.

FIG. 16 is a side view of one embodiment of an expander apparatus in areduced profile configuration.

FIG. 17 is a side view of the expander apparatus of FIG. 16 in anexpanded configuration.

FIG. 18 is a sectional view of the expander apparatus of FIGS. 16-17inserted into the access device of FIG. 2, which has been inserted intoa patient.

FIG. 19 is a sectional view of the expander apparatus of FIGS. 16-17inserted into the access device of FIG. 2 and expanded to the expandedconfiguration to retract tissue.

FIG. 20 is an exploded perspective view of one embodiment of anendoscope mount platform.

FIG. 21 is a top view of the endoscope mount platform of FIG. 20 coupledwith one embodiment of an indexing arm and one embodiment of anendoscope.

FIG. 22 is a side view of the endoscope mount platform of FIG. 20illustrated with one embodiment of an indexing arm and one embodiment ofan endoscope.

FIG. 23 is a perspective view of one embodiment of an indexing collar ofthe endoscope mount platform FIG. 20.

FIG. 24 is a perspective view of one embodiment of an endoscope.

FIG. 25 is a partial sectional view of one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 26 is a perspective view of one embodiment of a fastener.

FIG. 27 is an exploded perspective view of the fastener of FIG. 26.

FIG. 27( a) is an enlarged side view of one embodiment of a biasingmember illustrated in FIG. 27 taken from the perspective of the arrow 27a.

FIG. 28 is a perspective view of one embodiment of a surgicalinstrument.

FIG. 29 is an enlarged sectional view of the fastener of FIGS. 26-27coupled with the surgical instrument of FIG. 28, illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 30 is side view of one embodiment of another surgical instrument.

FIG. 31 is a partial sectional view of one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 32 is a side view of one embodiment of another surgical instrument.

FIG. 33 is a perspective view similar to FIG. 31 illustrating theapparatuses of FIGS. 26 and 32, in one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 34 is an enlarged sectional view of the apparatus of FIGS. 26 and32, illustrating one embodiment of a stage of one embodiment of a methodfor treating the spine of a patient.

FIG. 35 is an enlarged sectional similar to FIG. 34, illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 36 is an enlarged view in partial section illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 37 is a partial view of illustrating one embodiment of a stage ofone embodiment of a method for treating the spine of a patient.

FIG. 38 is a perspective view of a spinal implant or fusion deviceconstructed according to another embodiment showing a first side surfaceof the spinal implant.

FIG. 39 is a perspective view of the spinal implant of FIG. 38 showing asecond side surface of the spinal implant.

FIG. 40 is a plan view of the spinal implant of FIG. 38 showing an uppersurface of the spinal implant.

FIG. 41 is a side view of the spinal implant of FIG. 38 showing thefirst side surface.

FIG. 42 is a cross-sectional view of the spinal implant taken along theline 42-42 in FIG. 41.

FIG. 43 is a perspective view of another embodiment of a spinal implantconstructed according to another embodiment showing a first side surfaceof the spinal implant.

FIG. 44 is a perspective view of the spinal implant of FIG. 43 showing asecond side surface of the spinal implant.

FIG. 45 is a plan view of the spinal implant of FIG. 43 showing an uppersurface of the spinal implant.

FIG. 46 is a side view of the spinal implant of FIG. 43 showing thefirst side surface.

FIG. 47 is a cross-sectional view of the spinal implant taken along theline 47-47 in FIG. 46.

FIG. 48 is a view showing a pair of the spinal implants of FIG. 38 infirst relative positions between adjacent vertebrae.

FIG. 49 is a view showing a pair of the spinal implants of FIG. 38 insecond relative positions between adjacent vertebrae.

FIG. 50 is a view showing the spinal implant of FIG. 43 between adjacentvertebrae.

FIG. 51 is a view showing a spinal implant being inserted between theadjacent vertebrae according to another embodiment.

FIG. 52 is a side view of an apparatus according to another embodiment.

FIG. 53 is a front view of the apparatus of FIG. 52.

FIG. 54 is a top view of the apparatus of FIG. 52.

FIG. 55 is a back view of the apparatus of FIG. 52.

FIG. 56 is a bottom view of the apparatus of FIG. 52.

FIG. 57 is a sectional view of the apparatus of FIG. 52, used inconjunction with additional structure in a patient.

FIG. 58 is a longitudinal sectional view of the apparatus of FIG. 57taken from line 58-58 of FIG. 57.

FIG. 59 is a transverse sectional view of the apparatus of FIG. 58 takenfrom line 59-59 of FIG. 58.

FIG. 60 is a sectional view, similar to FIG. 57, illustrating analternative position of the apparatus of FIG. 52.

FIG. 61 is a sectional view, similar to FIG. 57, illustrating anotheralternative position of the apparatus of FIG. 52.

FIG. 62 is a transverse sectional view of the apparatus of FIG. 61,taken along lines 62-62 of FIG. 61.

FIG. 63 is a side view, similar to FIG. 52, of another apparatus.

FIG. 64 is a front view, similar to FIG. 55, of the embodiment of FIG.63.

FIG. 65 is a sectional view, similar to FIG. 57, of the apparatus ofFIG. 63, used in conjunction with additional structure in a patient.

FIG. 66 is a transverse sectional view of the apparatus of FIG. 63,taken along lines 66-66 of FIG. 65.

FIG. 67 is a perspective view of an access device according to anotherembodiment.

FIG. 68 is a side perspective view of the access device of FIG. 67.

FIG. 69 is a perspective view of the access device of FIG. 67 in apivoted configuration.

FIG. 70 is an end view of the access device of FIG. 67.

FIG. 71 is an exploded perspective view of the access device of FIG. 67in an expanded configuration with some portions shown in hidden line.

FIG. 72 is a perspective view of the access device of FIG. 67 in acontracted configuration with some portions shown in hidden line.

FIG. 73 is a partial sectional view of the access device of FIG. 67 inan early stage of a procedure.

FIG. 74 is a perspective view of a portion of one embodiment of asurgical system that includes an access device, a support arm, and alighting element shown applied to a patient.

FIG. 75 is a perspective side view of the surgical system of FIG. 74shown applied to a patient.

FIG. 76 is a top view of the surgical system of FIG. 74.

FIG. 77 is a perspective view of one embodiment of a lighting element.

FIG. 78 is a perspective view of another embodiment of a lightingelement.

FIG. 79 is a perspective view of another embodiment of a lightingelement.

FIG. 80 is a perspective view of an access assembly.

FIG. 81 is an exploded perspective view of the access assembly of FIG.80.

FIG. 82 is a side view of an access device of the access assembly ofFIG. 80, the access device having a lock to maintain a state ofexpansion thereof.

FIG. 83 is a cross-sectional view of the access device of FIG. 82 takenalong section plane 83-83.

FIG. 83A is a detail view of one embodiment of a lock to maintain astate of expansion of an access device, the lock shown in the lockedposition.

FIG. 83B is a detail of the lock of FIG. 83A, the lock shown in theunlocked position.

FIG. 84 is a cross-section view similar to that of FIG. 83 with the lockdevice in the unlocked position during the un-expansion of the accessdevice.

FIGS. 85 and 85A are top perspective and detailed views respectively ofthe access device of FIG. 82 with the lock in a locked position.

FIGS. 86 and 86A are top perspective and detailed views respectively ofthe access device of FIG. 82 with the lock in an unlocked position.

FIG. 87 is a top view of a viewing element mounting assembly having alight post mount or visualization mount, according to one embodiment.

FIG. 88 is a side view of the viewing element mounting assembly of FIG.87.

FIG. 89 is a perspective view of the light post mount or visualizationmount of FIG. 87.

FIG. 90 is a top view of the light post mount or visualization mount ofFIG. 89.

FIG. 91 is a side cross section view of the light post mount orvisualization mount of FIG. 89.

FIG. 92 is a bottom view of the light post mount or visualization mountof FIG. 89.

FIG. 93 is a side view of a support portion of the light post mount orvisualization mount of FIG. 89.

FIG. 94 is a schematic view of the cross section of a passage of thelight post mount or visualization mount of FIG. 89.

FIG. 95 is an end view showing a spline surface of a spline ring for thelight post mount or visualization mount of FIG. 89.

FIG. 96 is a side view of the spline ring of FIG. 95.

FIG. 97 is another end view of the spline ring of FIG. 95.

FIG. 98 is a top view of a light post or visualization element,according to one embodiment.

FIG. 99 is a side view of the light post or visualization element ofFIG. 98.

FIG. 100 is a front view of a light post mount block or visualizationelement mount block, according to one embodiment.

FIG. 101 is a side view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 102 is a top view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 103 is a side cross section view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 104 is a back view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 105 is a top perspective view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 106 is a bottom perspective view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 107 illustrates a pin configured to be coupled with the light postmount block or visualization element mount block of FIG. 100.

FIG. 108 is a top view of an indexing collar assembly, having anindexing collar, according to one embodiment.

FIG. 109 is a side view of the indexing collar assembly of FIG. 108.

FIG. 110 is an end cross section view of the indexing collar of FIG.108.

FIG. 111 is an end view of the indexing collar of FIG. 108.

FIG. 112 is a schematic view of a passage of the indexing collar of FIG.108.

FIG. 113 is a top view of the indexing collar of FIG. 108.

FIG. 114 is a side view of the indexing collar of FIG. 108.

FIG. 115 is a side cross section view of the indexing collar of FIG.108.

FIG. 116 is a bottom view of the indexing collar of FIG. 108.

FIG. 117 illustrates a portion of the indexing collar of FIG. 108.

FIG. 118 is a bottom perspective view of the indexing collar of FIG.108.

FIG. 119 is a top perspective view of the indexing collar of FIG. 108.

FIG. 120 is a side view of an oval or oblong shaped dilator, accordingto one embodiment.

FIG. 121 is an end view of the dilator of FIG. 120.

FIG. 122 is another side view of the dilator of FIG. 120.

FIG. 123 is a side view of an access device assembly in a low profileconfiguration, according to one embodiment.

FIG. 124 is a front view of the access device assembly of FIG. 123.

FIG. 125 is a top view of the access device assembly of FIG. 123 in anexpanded configuration.

FIG. 126 is a front view of the access device assembly of FIG. 123 in anexpanded configuration.

FIG. 127 is a cross section view of a lock coupling location of theaccess device assembly of FIG. 123, taken along section plane 127-127.

FIG. 128 is a cross section view of a skirt coupling location of theaccess device assembly of FIG. 123, taken along section plane 128-128.

FIG. 129 is a cross section view of a proximal portion coupling locationof the access device assembly of FIG. 123, taken along section plane129-129.

FIG. 130 is a top view of a proximal portion of the access device ofFIG. 123.

FIG. 131 is a front view of the proximal portion of the access device ofFIG. 123.

FIG. 132 is a side view of the proximal portion of the access device ofFIG. 123.

FIG. 133 illustrates a first locking skirt portion of a distal portionof the access device of FIG. 123.

FIG. 134 illustrates a second locking skirt portion of the distalportion of the access device of FIG. 123.

FIG. 135 is a side view of a locking element of the access device ofFIG. 123.

FIG. 136 is a side view of a locking element of the access device ofFIG. 123.

FIG. 137 is a side view of a locking element of the access device ofFIG. 123.

FIG. 138 illustrates a friction washer of the access device of FIG. 123.

FIG. 139 is a side view of an access device assembly in a low profileconfiguration, according to another embodiment.

FIG. 140 is a front view of the access device assembly of FIG. 139.

FIG. 141 is a top view of the access device assembly of FIG. 139 in anexpanded configuration.

FIG. 142 is a front view of the access device assembly of FIG. 139 in anexpanded configuration.

FIG. 143 is a cross section view of a lock coupling location of theaccess device assembly of FIG. 139, taken along section plane 143-143.

FIG. 144 is a cross section view of a skirt coupling location of theaccess device assembly of FIG. 139, taken along section plane 144-144.

FIG. 145 is a cross section view of a proximal portion coupling locationof the access device assembly of FIG. 139, taken along section plane145-145.

FIG. 146 is a top view of a proximal portion of the access device ofFIG. 139.

FIG. 147 is a front view of the proximal portion of the access device ofFIG. 139.

FIG. 148 is a side view of the proximal portion of the access device ofFIG. 139.

FIG. 149 illustrates a first locking skirt portion of a distal portionof the access device of FIG. 139.

FIG. 150 illustrates a second locking skirt portion of the distalportion of the access device of FIG. 139.

FIG. 151 is an exploded perspective view of a surgical cannula accordingto one embodiment of the present invention, the cannula being shown inan expanded condition.

FIG. 152 is a perspective view of the cannula of FIG. 151 with partsremoved for clarity, the cannula being shown in a contracted condition.

FIG. 153 is a schematic end view showing the cannula of FIG. 151 in theexpanded condition.

FIG. 154 is a rollout view of a part of the cannula of FIG. 151.

FIG. 155 is a schematic sectional view of the cannula of FIG. 151 duringa surgical procedure.

FIG. 156 is a schematic view of a support apparatus constructedaccording to another embodiment.

FIG. 157 is a schematic view taken along line 157-157 in FIG. 156.

FIG. 158 is a schematic view taken along line 158-158 in FIG. 156showing part of the support of FIG. 156.

FIG. 159 is a schematic view taken along line 159-159 in FIG. 156showing part of the support apparatus of FIG. 156.

FIG. 160 is a schematic view taken along line 160-160 in FIG. 156 withparts removed.

FIG. 161 is a schematic view taken along line 161-161 in FIG. 156.

FIG. 162 is a schematic view taken along line 162-162 in FIG. 156showing part of the support apparatus of FIG. 156.

FIG. 163 is a schematic view taken along line 163-163 in FIG. 156showing part of the support apparatus of FIG. 156.

FIG. 164 is a perspective view of the support apparatus of FIG. 156.

FIG. 165 is a perspective view of the support apparatus of FIG. 156looking at the support apparatus from an angle different than FIG. 163.

FIG. 166 is a perspective view of the support apparatus of FIG. 156looking at the support apparatus from an angle different than FIGS. 164and 165.

FIG. 167 is a sectional view taken approximately along line 167-167 ofFIG. 159.

FIG. 168 is an enlarged view of a part of FIG. 167.

FIG. 169 is a schematic view taken along line 169-169 in FIG. 160 withparts removed.

FIG. 170 is a view further illustrating parts shown in FIG. 160.

FIG. 171 is a view taken approximately along line 171-171 of FIG. 170.

FIG. 172 is a schematic view showing the support apparatus with anassociated known mechanical arm.

FIG. 173 is a schematic view of another feature of part of the supportapparatus of FIG. 156.

FIG. 174 is a schematic view of a fixation assembly attached tovertebrae of a patient.

FIG. 175 is a schematic view taken along line 175-175 of FIG. 174.

FIG. 176 is an exploded schematic view of part of the assembly of FIG.174.

FIG. 177 is a schematic view of another fixation assembly attached tovertebrae of a patient.

FIG. 178 is a schematic view taken along line 178-178 of FIG. 177.

FIG. 179 is an exploded schematic view of part of the assembly of FIG.177.

FIG. 180 is an exploded view of part of a cutting tool according toanother embodiment.

FIG. 181 is an assembled view of part of the cutting tool of FIG. 180.

FIG. 182 is a perspective view of one embodiment of a surgical assembly.

FIG. 183 is a schematic view of an expandable access device in acontracted state and in an expanded state (in phantom).

FIG. 184 is a bottom view of a distal portion of one embodiment of anaccess device illustrating a first overlapping arrangement.

FIG. 185 is a bottom view of a distal portion of another embodiment ofan access device illustrating a second overlapping arrangement.

FIG. 186 is a schematic view of another embodiment of an expandableaccess device having an expansion mechanism.

FIG. 187 is a plan view of a proximal portion of an access device, thedistal portion shown schematically.

FIG. 188 is a perspective view of the proximal portion of the accessdevice of FIG. 187.

FIG. 189 schematically illustrates one approach to expanding or reducingthe cross-sectional size of the proximal portion of the access device ofFIG. 187.

FIG. 190 is a perspective view of one embodiment of an access assembly,showing a proximal portion thereof.

FIG. 191 is a perspective view of another embodiment of an accessassembly, showing a proximal portion thereof with a stretchable cover.

FIG. 192 is a perspective view of a proximal end of a proximal portionof one embodiment of an access device, the proximal end having aplurality of notches, with a portion of an access device mountingfixture shown in phantom.

FIG. 193 is a perspective proximal end view of an access device having apivot rivet.

FIG. 194 is a perspective view of a proximal portion of one embodimentof an access device having a ratchet arrangement.

FIG. 195 is a partial top schematic view of the access device of FIG.194.

FIG. 196 is a perspective view of another embodiment of an accessdevice, which includes an expandable proximal portion and an expandabledistal portion.

FIG. 197 is a plan view of one variation of the access device of FIG.196, illustrating a first configuration for inserting the access deviceinto a patient.

FIG. 198 is a plan view of another variation of the access device ofFIG. 196, which has actuating rods located on the proximal portion.

FIG. 199 illustrates another embodiment of an access device in a lowprofile configuration, having an expandable distal portion withdeployment teeth to fix the extent of the expansion of the distalportion.

FIG. 200 is a side view of the access device of FIG. 199 in an expandedconfiguration.

FIG. 201 includes a plurality of views illustrating the expansion of theaccess device of FIG. 199.

FIG. 202 illustrates one embodiment of an access device having aninflatable portion.

FIG. 203 is a cross section view of the access device of FIG. 202.

FIG. 204 is a plan view of another embodiment of an access device withinterleaved semi-circular bands that can pivot in a track.

FIG. 205 is another embodiment of an access device that has a thinstainless steel weave and an elastomeric overmold, the access devicebeing expandable upon longitudinal compression.

FIG. 206 is a side view of the access device of FIG. 205 in the expandedconfiguration.

FIG. 207 is a cross-sectional view of another embodiment of an accessdevice having a partial ball joint located between a proximal and adistal portion.

FIG. 208 is a schematic view of another embodiment of an inflatableaccess device that is shown applied across a patient's skin, the accessdevice having a positionable passageway.

FIG. 209 is a perspective view of another embodiment of an access devicehaving an oval proximal end and three leaves.

FIG. 210 is a perspective view of another embodiment of an access devicehaving a flexible mesh, the access device being expandable.

FIG. 211 is a perspective view of an access device having a curvilinearproximal portion (e.g., round or oval in transverse cross-section), adistal portion including elongate elements that fan-out to an enlargeddistal end, and an intermediate portion located between the proximal endand the distal end.

FIG. 212 is a perspective view of an access device having an expandabledistal portion including elongate members with mesh material and amovable proximal portion, shown in the expanded condition.

FIG. 213 is a perspective view of the access device of FIG. 212, shownin a low profile configuration.

FIG. 214 is a perspective view of an access device having an expandabledistal portion including elongate members made of wire and a movableproximal portion, shown in the expanded condition.

FIG. 215 is a perspective view of the access device of FIG. 214, shownin a low profile configuration.

FIG. 216 is an exploded perspective view of an access device having anexpandable skirt connected to a collar at the proximal end at a pivotpoint.

FIG. 217 is a side view of a skirt portion of the access device of FIG.216.

FIG. 218 is a side view of the access device of FIG. 216, in a contactedposition.

FIG. 219 is a side view of the access device of FIG. 216, in an expandedposition.

FIG. 220 is a cross-sectional view of one embodiment of an access devicewith an expander tool inserted therein.

FIG. 221 is a perspective view of one embodiment of a longitudinallyextending side of a distal portion of one embodiment of an accessdevice.

FIG. 222 is a cross-sectional view of a portion of an access device witha deployment mechanism, the deployment mechanism in the un-deployedposition.

FIG. 223 is a cross-sectional view of the access device of FIG. 222, thedeployment mechanism being in a deployed position.

FIG. 224 is an exploded view of a portion of the access device of FIG.222.

FIG. 225 is a perspective view of another embodiment of an access devicehaving a distal portion with an inserted configuration, wherein thedistal portion is capable of being locked in the inserted configuration.

FIG. 226 is a cross-sectional view of access device of FIG. 225 takenalong section plane 226-226 illustrating one embodiment of a lock.

FIG. 227 is a partial distal-end view of an access device similar to theaccess device illustrated in FIG. 225, showing another embodiment of alock.

FIG. 228 is a partial distal-end view of an access device similar to theaccess device illustrated in FIG. 225, showing another embodiment of alock.

FIG. 229 is a perspective view of one access device embodiment havinglocking features.

FIG. 230 is a perspective view of another access device embodimenthaving locking features.

FIG. 231 is a cross section view of a locking element of FIG. 230.

FIG. 232 is a perspective view of a retractor with expandable lockingblades and an expandable shroud, shown in a tubular configuration forinsertion over a dilator.

FIG. 233 is a perspective view of the retractor of FIG. 232, showingcomponents in hidden lines in a partially expanded condition.

FIG. 234 is a perspective view of the retractor of FIG. 232, showingcomponents in hidden lines in a fully expanded condition.

FIG. 234A is a schematic view illustrating one method of inserting aspinal implant into an interbody space through the retractor of FIG.232.

FIG. 235 is a perspective view of another access device embodiment, withan expandable locking distal portion and an oblong shaped proximalportion with a multi-pivot configuration, shown in an expanded lockedposition.

FIG. 236 is an exploded perspective view of the access device of FIG.235, showing pivot components of the access device.

FIG. 237 is a front view of the access device of FIG. 235.

FIG. 238 is a side view of the access device of FIG. 235, showing theproximal portion in a pivoted position.

FIG. 239 is a top view of the access device of FIG. 235.

FIG. 240 is a perspective view of an obturator and an access deviceaccording to one embodiment, with the access device positioned on theobturator for insertion into a patient.

FIG. 241 is a side view of the obturator of FIG. 240.

FIG. 242 is a perspective view of an oblong shaped obturator and anaccess device according to one embodiment, with the access devicepositioned on the obturator for insertion into a patient.

FIG. 243 is a perspective view of the obturator and access device ofFIG. 242.

FIG. 244 is a perspective view of one embodiment of a viewing elementmounting fixture for adjustably coupling a viewing element to an accessdevice mounting fixture.

FIG. 245 is a perspective view of another embodiment of a surgicalassembly.

FIG. 246 is a perspective view of another embodiment of a surgicalassembly.

FIG. 247 is a perspective view of another embodiment of a surgicalassembly.

FIG. 248 is a top view of a portion of the surgical assembly of FIG. 247illustrating two positions in which a viewing element thereof may bepositioned.

FIG. 249 is a perspective view of another embodiment of a viewingassembly for adjustably coupling a viewing element to an access devicemounting fixture.

FIG. 250 is a schematic view of a ratchet arrangement for expansion andun-expansion of a portion of a surgical assembly (e.g., an access devicemounting fixture, an access device proximal end, or an access devicedistal end).

FIG. 251 is a schematic top view of the ratchet arrangement of FIG. 250.

FIG. 252 is a perspective view of a viewing element mount including aclamp and a slot.

FIG. 253 is a cross section side view of the viewing element mount ofFIG. 252.

FIG. 254 is a perspective view of a viewing element mount including aC-clamp.

FIG. 255 is a side view of the viewing element mount of FIG. 254.

FIG. 256 is a perspective view of a viewing element mount using a vacuumsource to position the mount on a mount support.

FIG. 257 is a side view of the viewing element mount in FIG. 256.

FIG. 258 is a perspective view of a viewing element mount having asuction cup for positioning the mount on a support.

FIG. 259 is a schematic view showing various stages of suction for theviewing element mount of FIG. 258.

FIG. 260 is a schematic view of a suction mechanism for a viewingelement mount.

FIG. 261 is a schematic view showing various stages of suction for thesuction mechanism of FIG. 260.

FIG. 262 is one embodiment of a surgical assembly having a view elementmounting fixture including a ball joint.

FIG. 263 is a perspective view of another embodiment a viewing assemblyfor adjustably coupling a viewing element to an access device mountingfixture.

FIG. 264 is a perspective view of another embodiment of a viewingelement mounting fixture for adjustably coupling a viewing element to anaccess device mounting fixture.

FIG. 265 is a perspective view of one embodiment of a clamp for fixingthe position of a viewing element.

FIG. 266 is a partial cross sectional view of the clamp of FIG. 265.

FIG. 267 is a top view of one embodiment of an access device mountingfixture for adjustably supporting an access device.

FIG. 268 is a perspective view of another embodiment of an access devicemounting fixture for adjustably supporting an access device.

FIG. 269 is a detail view of a portion of the access device mountingfixture of FIG. 268.

FIG. 270 is a top plan view of another embodiment of an access devicemounting fixture.

FIG. 271 is a perspective view of one embodiment of a viewing elementmounting fixture for adjustably coupling a viewing element to an accessdevice mounting fixture.

FIG. 272 is a schematic view of a viewing element of FIG. 271.

FIG. 273 is a perspective view of one embodiment of a viewing elementmounting fixture having a C linkage.

FIG. 274 is another embodiment of a viewing element mounting fixturehaving a coiled spring arrangement.

FIG. 275 is a perspective view of another embodiment of a viewingelement mounting fixture with a viewing element pivot mount and avisualization window.

FIG. 276 is a perspective view of another embodiment of a viewingelement mounting fixture.

FIG. 277 is a schematic view of the freedom of rotation for the viewingelement of FIG. 276.

FIG. 278 is a schematic side view of the viewing element mountingfixture of FIG. 276.

FIG. 279 is a schematic top view of the viewing element mounting fixtureof FIG. 276.

FIG. 280 is a schematic view of the pivot range and positionability ofthe viewing element of FIG. 276.

FIG. 281 is a perspective view of another embodiment of an access devicemounting fixture.

FIG. 282 is a schematic top view of the access device mounting fixtureof FIG. 281.

FIG. 283 is a schematic side view of the access device mounting fixtureof FIG. 281 coupled with an access device.

FIG. 284 is a perspective view of a surgical assembly having athumb-wheel lock and/or a cam lever lock.

Throughout the figures, the same reference numerals and characters,unless otherwise stated, are used to denote like features, elements,components or portions of the illustrated embodiments. Moreover, whilethe subject matter of this application will now be described in detailwith reference to the figures, it is done so in connection with theillustrative embodiments. It is intended that changes and modificationscan be made to the described embodiments without departing from the truescope and spirit of the subject invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As should be understood in view of the following detailed description,this application is primarily directed to, though not necessarilylimited to, apparatuses and methods for treating the spine of a patientthrough an access device. More particularly, the systems described belowprovide access to surgical locations at or near the spine and provide avariety of tools useful in performing treatment of the spine. Also, thesystems described herein enable a surgeon to perform a wide variety ofmethods as described herein.

I. Systems for Performing Procedures at a Surgical Location

Various embodiments of apparatuses and procedures described herein willbe discussed in terms of minimally invasive procedures and apparatuses,e.g., of endoscopic apparatuses and procedures. However, many aspects ofthe present invention may find use in conventional, open, and mini-openprocedures. As used herein, the term “proximal,” as is traditional,refers to the end portion of the apparatus that is closest to theoperator, while the term “distal” refers to the end portion that isfarthest from the operator.

FIG. 1 shows one embodiment of a surgical system 10 that can be used toperform a variety of methods or procedures. In one embodiment, asdiscussed more fully below, the patient P is placed in the proneposition on operating table T, taking care that the abdomen is notcompressed and physiological lordosis is preserved. The physician D isable to access the surgical site and perform the surgical procedure withthe components of the system 10, which will be described in greaterdetail herein. The system 10 may be supported, in part, by a mechanicalsupport arm A, such as the type generally disclosed in U.S. Pat. No.4,863,133, which is hereby incorporated by reference herein in itsentirety. One mechanical arm of this type is manufactured by LeonardMedical, Inc., 1464 Holcomb Road, Huntington Valley, Pa., 19006.

Visualization of the surgical site may be achieved in any suitablemanner, e.g., by use of a viewing element, such as an endoscope, acamera, loupes, a microscope, direct visualization, or any othersuitable viewing element, or a combination of the foregoing. In oneembodiment, the viewing element provides a video signal representingimages, such as images of the surgical site, to a monitor M. The viewingelement may be an endoscope and camera that captures images to bedisplayed on the monitor M whereby the physician D is able to view thesurgical site as the procedure is being performed. The endoscope andcamera will be described in greater detail herein.

The systems are described herein in connection with minimally invasivepostero-lateral spinal surgery. One such procedure is a two levelpostero-lateral fixation and fusion of the spine involving the L4, L5,and S1 vertebrae. In the drawings, the vertebrae will generally bedenoted by reference letter V. The usefulness of the apparatuses andprocedures is neither restricted to the postero-lateral approach nor tothe L4, L5, and S1 vertebrae. The apparatuses and procedures may be usedin other anatomical approaches and with other vertebra(e) within thecervical, thoracic, and lumbar regions of the spine. The procedures maybe directed toward surgery involving one or more vertebral levels. Someembodiments are useful for anterior and/or lateral procedures. Moreover,it is believed that embodiments of the invention are also particularlyuseful where any body structures must be accessed beneath the skin andmuscle tissue of the patient, and/or where it is desirable to providesufficient space and visibility in order to manipulate surgicalinstruments and treat the underlying body structures. For example,certain features or instrumentation described herein are particularlyuseful for minimally invasive procedures, e.g., arthroscopic procedures.As discussed more fully below, one embodiment of an apparatus describedherein provides an access device that has an expandable distal portion.In addition to providing greater access to a surgical site than would beprovided with device having a constant cross-section, the expandabledistal portion prevents or substantially prevents the access device, orinstruments extended therethrough to the surgical site, from dislodgingor popping out of the operative site.

In one embodiment, the system 10 includes an access device that providesan internal passage for surgical instruments to be inserted through theskin and muscle tissue of the patient P to the surgical site. The term“access device” is used in its ordinary sense to mean a device that canprovide access and is a broad term and it includes structures having anelongated dimension and defining a passage, e.g., a cannula or aconduit. The access device is configured to be inserted through the skinof the patient to provide access during a surgical procedure to asurgical location within a patient, e.g., a spinal location. The term“surgical location” is used in its ordinary sense (i.e. a location wherea surgical procedure is performed) and is a broad term and it includeslocations subject to or affected by a surgery. The term “spinallocation” is used in its ordinary sense (i.e. a location at or near aspine) and is a broad term and it includes locations adjacent to orassociated with a spine that may be sites for surgical spinalprocedures. The access device also can retract tissue to provide greateraccess to the surgical location.

The access device preferably has a wall portion defining a reducedprofile configuration for initial percutaneous insertion into thepatient. This wall portion may have any suitable arrangement. In oneembodiment, discussed in more detail below, the wall portion has agenerally tubular configuration that may be passed over a dilator thathas been inserted into the patient to atraumatically enlarge an openingsufficiently large to receive the access device therein.

The wall portion of the access device preferably can be subsequentlyexpanded to an enlarged configuration, by moving against the surroundingmuscle tissue to at least partially define an enlarged surgical space inwhich the surgical procedures will be performed. In a sense, it acts asits own dilator. The access device may also be thought of as aretractor, and may be referred to herein as such. Both the distal andproximal portion may be expanded, as discussed further below. However,the distal portion preferably expands to a greater extent than theproximal portion, because the surgical procedures are to be performed atthe surgical site, which is adjacent the distal portion when the accessdevice is inserted into the patient.

While in the reduced profile configuration, the access device preferablydefines a first unexpanded configuration. Thereafter, the access devicecan enlarge the surgical space defined thereby by engaging the tissuesurrounding the access device and displacing the tissue outwardly as theaccess device expands. The access device preferably is sufficientlyrigid to displace such tissue during the expansion thereof. The accessdevice may be resiliently biased to expand from the reduced profileconfiguration to the enlarged configuration. In addition, the accessdevice may also be manually expanded by an expander device with orwithout one or more surgical instruments inserted therein, as will bedescribed below. The surgical site preferably is at least partiallydefined by the expanded access device itself. During expansion, theaccess device can move from a first overlapping configuration to asecond overlapping configuration.

In some embodiments, the proximal and distal portions are separatecomponents that may be coupled together in a suitable fashion. Forexample, the distal end portion of the access device may be configuredfor relative movement with respect to the proximal end portion in orderto allow the physician to position the distal end portion at a desiredlocation. This relative movement also provides the advantage that theproximal portion of the access device nearest the physician D may remainsubstantially stable during such distal movement. In one embodiment, thedistal portion is a separate component that is pivotally or movablycoupled with the proximal portion. In another embodiment, the distalportion is flexible or resilient in order to permit such relativemovement.

A. Systems and Devices for Establishing Access

1. Access Devices

One embodiment of an access device is illustrated in FIGS. 2-6 anddesignated by reference number 20. In one embodiment, the access device20 includes a proximal wall portion 22 that has a tubular configuration,and a distal wall portion that has an expandable skirt portion 24. Theskirt portion 24 preferably is enlargeable from a reduced profileconfiguration having an initial dimension 26 (illustrated in FIG. 2) andcorresponding cross-sectional area, to an enlarged configuration havinga second dimension 28 (illustrated in FIG. 4) and correspondingcross-sectional area. In one embodiment, the skirt portion 24 is coupledwith the proximal wall portion 22 with a rivet 30, pin, or similarconnecting device to permit movement of the skirt portion 24 relative tothe proximal wall portion 22.

In the illustrated embodiment, the skirt portion 24 is manufactured froma resilient material, such as stainless steel. The skirt portion 24preferably is manufactured so that it normally assumes an expandedconfiguration as illustrated in FIG. 4. With reference to FIG. 3, theskirt portion 24 may assume an intermediate dimension 34 andcorresponding cross-sectional area, which is greater than the initialdimension 26 of the reduced profile configuration of FIG. 2, and smallerthan the dimension 28 of the enlarged configuration of FIG. 4. The skirtportion 24 may assume the intermediate configuration of FIG. 3 whendeployed in the patient in response to the force of the tissue acting onthe skirt portion 24. The intermediate dimension 34 can depend uponseveral factors, such as the rigidity of the skirt portion 24, thesurrounding tissue, and whether such surrounding tissue has relaxed ortightened during the course of the procedure. An outer sleeve 32(illustrated in dashed line in FIG. 2) may be provided. Preferably, theouter sleeve surrounds the access device 20 and maintains the skirtportion 24 in the reduced profile configuration prior to insertion intothe patient. The outer sleeve 32 may be made of plastic. Where provided,the outer sleeve 32 preferably is configured to be easily deployed. Forexample, a release device may be provided that releases or removes theouter sleeve 32 upon being operated by the user. In one embodiment, abraided polyester suture is embedded within the sleeve 32, alignedsubstantially along the longitudinal axis thereof. In use, when thesuture is withdrawn, the outer sleeve 32 is torn, allowing the accessdevice 20 to resiliently expand from the reduced profile configurationof FIG. 2 to the expanded configurations of FIGS. 3-4. While in thereduced profile configuration of FIG. 2, the skirt portion 24 defines afirst overlapping configuration 33, as illustrated by the dashed line.As the skirt portion 24 resiliently expands, the skirt portion 24assumes the expanded configuration, as illustrated in FIGS. 3-4.

The skirt portion 24 preferably is sufficiently rigid that it is capableof displacing the tissue surrounding the skirt portion 24 as it expands.Depending upon the resistance exerted by surrounding tissue, the skirtportion 24 preferably is sufficiently rigid to provide some resistanceagainst the tissue to remain in the configurations of FIGS. 3-4.Moreover, the expanded configuration of the skirt portion 24 is at leastpartially supported by the body tissue of the patient. The rigidity ofthe skirt portion 24 and the greater expansion at the distal portionpreferably creates a stable configuration that is at least temporarilystationary in the patient. This arrangement preferably frees thephysician from the need to actively support the access device 20, e.g.,prior to adding an endoscope mount platform 300 and a support arm 400(see FIGS. 21-22).

One embodiment of the skirt portion 24 of the access device 20 isillustrated in an initial flattened configuration in FIG. 5. The skirtportion 24 may be manufactured from a sheet of stainless steel having athickness of about 0.007 inches (0.178 mm). In various embodiments, thedimension 28 of the skirt portion 24 is about equal to or greater than50 mm, is about equal to or greater than 60 mm, is about equal to orgreater than 70 mm, is about equal to or greater than 80 mm, or is anyother suitable size, when the skirt portion 24 is in the enlargedconfiguration. In one embodiment, the dimension 28 is about 63 mm, whenthe skirt portion 24 is in the enlarged configuration. The unrestrictedshape of the skirt portion 24 is a circular shape in one embodiment andis an oblong shape in another embodiment. In another embodiment, theskirt portion 24 has an oval shape, wherein the dimension 28 defines alonger dimension of the skirt portion 24 and would be about 85 mm. Inanother embodiment, the skirt portion 24 has an oval shape and thedimension 28 defines a longer dimension of the skirt portion 24 of about63 mm. An increased thickness, e.g., about 0.010 inches (0.254 mm), maybe used in connection with skirt portions having a larger diameter, suchas about 65 mm. Other materials, such as nitinol or plastics havingsimilar properties, may also be useful.

As discussed above, the skirt portion 24 preferably is coupled with theproximal wall portion 22 with a pivotal connection, such as rivet 30. Apair of rivet holes 36 can be provided in the skirt portion 24 toreceive the rivet 30. The skirt portion 24 also has two free ends 38 and40 in one embodiment that are secured by a slidable connection, such asa second rivet 44 (not shown in FIG. 5, illustrated in FIGS. 2-4). Apair of complementary slots 46 and 48 preferably are defined in theskirt portion 24 adjacent the free ends 38 and 40. The rivet 44 ispermitted to move freely within the slots 46 and 48. This slot and rivetconfiguration allows the skirt portion 24 to move between the reducedprofile configuration of FIG. 2 and the enlarged or expandedconfigurations of FIGS. 3-4. The use of a pair of slots 46 and 48reduces the risk of the “button-holing” of the rivet 44, e.g., asituation in which the opening of the slot becomes distorted andenlarged such that the rivet may slide out of the slot, and causefailure of the device. The likelihood of such occurrence is reduced inskirt portion 24 because each of the slots 46 and 48 in the double slotconfiguration has a relatively shorter length than a single slotconfiguration. Being shorter, the slots 46, 48 are less likely to bedistorted to the extent that a rivet may slide out of position. Inaddition, the configuration of rivet 44 and slots 46 and 48 permits asmoother operation of enlarging and reducing the skirt portion 24, andallows the skirt portion 24 to expand to span three or more vertebrae,e.g., L4, L5, and S1. This arrangement enables multi-level procedures,such as multilevel fixation procedures alone or in combination with avariety of other procedures, as discussed below. Other embodimentsinclude a single slot rather than the slots 46, 48, or more than twoslots.

An additional feature of the skirt portion 24 is the provision of ashallow concave profile 50 defined along the distal edge of the skirtportion 24, which allows for improved placement of the skirt portion 24with respect to the body structures and the surgical instruments definedherein. In one embodiment, a pair of small scalloped or notched portions56 and 58 are provided, as illustrated in FIG. 5. When the skirt portion24 is assembled, the notched portions 56 and 58 are generally acrossfrom each other. When the skirt portion 24 is applied to a patient, thenotched portions 56, 58 are oriented in the cephcaudal direction(indicated by a dashed line 60 in FIG. 4). In this arrangement,instruments and implants, such as an elongated member 650 used in afixation procedure (described in detail below), may extend beyond thearea enclosed by the skirt portion 24 without moving or raising theskirt portion 24, e.g., by allowing the elongated member 650 (or otherimplant or instrument) to pass under the skirt portion 24. The notchedportions 56, 58 also enable the elongated member 650 (or other implantor instrument) to extend beyond the portion of the surgical spacedefined within the outline of the distal end of the skirt portion 24.The notched portions 56, 58 are optional, as illustrated in connectionwith another embodiment of an access device 54, illustrated in FIG. 6,and may be eliminated if, for example, the physician deems the notchesto be unnecessary for the procedures to be performed. For example, insome fixation procedures such extended access is not needed, asdiscussed more fully below. As illustrated in FIG. 4, the skirt portion24 may be expanded to a substantially conical configuration having asubstantially circular or elliptical profile.

Furthermore, it is contemplated that the skirt portion 24 of the accessdevice 20 can include a stop that retains the skirt portion in anexpanded configuration, as shown in U.S. patent application Ser. No.10/361,887, filed Feb. 10, 2003, now U.S. Application Patent PublicationNo. US2003/153927 A1, which is hereby incorporated by reference in itsentirety herein.

In another embodiment, features may be provided on the skirt portion 24which facilitate the bending of the skirt portion at several locationsto provide a pre-formed enlarged configuration. For example, anotherembodiment of an access device 70, illustrated in FIGS. 7-9, provides askirt portion 74 that has four sections 76 a, 76 b, 76 c, 76 d having areduced thickness. For a skirt portion 74 having a thickness 78 of about0.007 inches (0.178 mm), reduced thickness sections 76 a, 76 b, 76 c, 76d may have a thickness 80 of about 0.002-0.004 inches (0.102 mm) (FIG.8). The reduced thickness sections 76 a, 76 b, 76 c, 76 d may have awidth 82 of about 1-5 mm. The thickness 78 of the skirt portion 74 maybe reduced by milling or grinding, as is known in the art. When theskirt portion 74 is opened, it moves toward a substantially rectangularconfiguration, as shown in FIG. 9, subject to the resisting forces ofthe body tissue. In another embodiment (not shown), a skirt portion maybe provided with two reduced thickness sections (rather than the fourreduced thickness sections of skirt 74) which would produce an oblong,substantially “football”-shaped access area.

FIGS. 10-12 show another embodiment of an access device 80. The accessdevice 80 has a skirt portion 84 with a plurality of perforations 86.The perforations 86 advantageously increase the flexibility at selectedlocations. The size and number of perforations 86 may vary dependingupon the desired flexibility and durability. In another embodiment, theskirt portion 84 may be scored or otherwise provided with a groove orrib in order to facilitate the bending of the skirt portion at thedesired location.

FIG. 13 illustrates another embodiment of an access device that has askirt portion 94 having one slot 96 and an aperture 98. A rivet (notshown) is stationary with respect to the aperture 98 and slides withinthe slot 96. FIG. 14 illustrates another embodiment of an access devicethat has a skirt portion 104 that includes an aperture 108. Theapertures 108 receives a rivet (not shown) that slides within elongatedslot 106.

Another embodiment of an access device comprises an elongate bodydefining a passage and having a proximal end and a distal end. Theelongate body has a proximal portion and a distal portion. The proximalportion has an oblong or generally oval shaped cross section in oneembodiment. The term “oblong” is used in its ordinary sense (i.e.,having an elongated form) and is a broad term and it includes astructure having a dimension, especially one of two perpendiculardimensions, such as, for example, width or length, that is greater thananother and includes shapes such as rectangles, ovals, ellipses,triangles, diamonds, trapezoids, parabolas, and other elongated shapeshaving straight or curved sides. The term “oval” is used in its ordinarysense (i.e., egg like or elliptical) and is a broad term and includesoblong shapes having curved portions.

The proximal portion comprises an oblong, generally oval shaped crosssection over the elongated portion. It will be apparent to those ofskill in the art that the cross section can be of any suitable oblongshape. The proximal portion can be any desired size. The proximalportion can have a cross-sectional area that varies from one end of theproximal portion to another end. For example, the cross-sectional areaof the proximal portion can increase or decrease along the length of theproximal portion. Alternatively, the proximal portion can have aconstant cross section over its length. Preferably, the proximal portionis sized to provide sufficient space for inserting multiple surgicalinstruments through the elongate body to the surgical location. Thedistal portion preferably is expandable and may comprise first andsecond overlapping skirt members. The degree of expansion of the distalportion is determined by an amount of overlap between the first skirtmember and the second skirt member in one embodiment.

The elongate body of the access device has a first location distal of asecond location. The elongate body preferably is capable of having aconfiguration when inserted within the patient wherein thecross-sectional area of the passage at the first location is greaterthan the cross-sectional area of the passage at the second location. Thepassage preferably is capable of having an oblong shaped cross sectionbetween the second location and the proximal end. In some embodimentsthe passage preferably is capable of having a generally elliptical crosssection between the second location and the proximal end. Additionally,the passage preferably is capable of having a non-circular cross sectionbetween the second location and the proximal end. Additionally, in someembodiments, the cross section of the passage can be symmetrical about afirst axis and a second axis, the first axis being generally normal tothe second axis. Other embodiments having an oblong cross-section arediscussed below in connection with FIGS. 67-73B.

Further details and features pertaining to access devices and systemsare described in U.S. Pat. No. 6,652,553, application Ser. No.10/361,887, filed Feb. 10, 2003, application Ser. No. 10/280,489, filedOct. 25, 2002, and application Ser. No. 10/678,744 filed Oct. 2, 2003,which are incorporated by reference in their entireties herein.

2. Dilators and Expander Devices

According to one embodiment of a procedure, an early stage involvesdetermining a point in the skin of the patient at which to insert theaccess device 20. The access point preferably corresponds to aposterior-lateral aspect of the spine. Manual palpation andAnterior-Posterior (AP) fluoroscopy may be used to determine preferredor optimal locations for forming an incision in the skin of the patient.In one application, the access device 20 preferably is placed midway (inthe cephcaudal direction) between the L4 through S1 vertebrae, centrallyabout 4-7 cm from the midline of the spine.

After the above-described location is determined, an incision is made atthe location. A guide wire (not shown) is introduced under fluoroscopicguidance through the skin, fascia, and muscle to the approximatesurgical site. A series of dilators is used to sequentially expand theincision to the desired width, about 23 mm in one procedure, preferablyminimizing damage to the structure of surrounding tissue and muscles. Afirst dilator can be placed over the guide wire to expand the opening.The guide wire may then be removed. A second dilator, slightly largerthan the first dilator, is placed over the first dilator to expand theopening further. Once the second dilator is in place, the first dilatormay be removed. This process of (1) introducing a next-larger-sizeddilator coaxially over the previous dilator and (2) optionally removingthe previous dilator(s) when the next-larger-sized dilator is in placecontinues until an opening of the desired size is created in the skin,muscle, and subcutaneous tissue. According to one application, thedesired opening size is about 23 mm. (Other dimensions of the opening,e.g., about 20 mm, about 27 mm, about 30 mm, etc., are also useful withthis apparatus in connection with spinal surgery, and still otherdimensions are contemplated.)

FIG. 15 shows that following placement of a dilator 120, which is thelargest dilator in the above-described dilation process, the accessdevice 20 is introduced in its reduced profile configuration andpositioned over the dilator 120. The dilator 120 is subsequently removedfrom the patient, and the access device 20 remains in position.

Once positioned in the patient, the access device 20 may be enlarged toprovide a passage for the insertion of various surgical instruments andto provide an enlarged space for performing the procedures describedherein. As described above, the access device may achieve theenlargement in several ways. In one embodiment, a distal portion of theaccess device may be enlarged, and a proximal portion may maintain aconstant diameter. The relative lengths of the proximal portion 22 andthe skirt portion 24 may be adjusted to vary the overall expansion ofthe access device 20. Alternatively, such expansion may extend along theentire length of the access device 20. In one application, the accessdevice 20 may be expanded by removing a suture 35 and tearing the outersleeve 32 surrounding the access device 20, and subsequently allowingthe skirt portion 24 to resiliently expand towards its fully expandedconfiguration as (illustrated in FIG. 4) to create an enlarged surgicalspace from the L4 to the S1 vertebrae. The resisting force exerted onthe skirt portion 24 may result in the skirt portion 24 assuming theintermediate configuration illustrated in FIG. 3. Under manycircumstances, the space created by the skirt portion 24 in theintermediate configuration is a sufficiently large working space toperform the procedure described herein. Once the skirt portion 24 hasexpanded, the rigidity and resilient characteristics of the skirtportion 24 preferably allow the access device 20 to resist closing tothe reduced profile configuration of FIG. 2 and to at least temporarilyresist being expelled from the incision. These characteristics create astable configuration for the access device 20 to remain in position inthe body, supported by the surrounding tissue. It is understood thatadditional support may be needed, especially if an endoscope is added.

According to one embodiment of a procedure, the access device 20 may befurther enlarged at the skirt portion 24 using an expander apparatus tocreate a surgical access space. An expander apparatus useful forenlarging the access device has a reduced profile configuration and anenlarged configuration. The expander apparatus is inserted into theaccess device in the reduced profile configuration, and subsequentlyexpanded to the enlarged configuration. The expansion of the expanderapparatus also causes the access device to be expanded to the enlargedconfiguration. In some embodiments, the expander apparatus may increasethe diameter of the access device along substantially its entire lengthin a generally conical configuration. In other embodiments, the expanderapparatus expands only a distal portion of the access device, allowing aproximal portion to maintain a relatively constant diameter.

In addition to expanding the access device, in some embodiments theexpander apparatus may also be used to position the distal portion ofthe access device at the desired location for the surgical procedure.The expander can engage an interior wall of the access device to movethe access device to the desired location. For embodiments in which thedistal portion of the access device is relatively movable with respectto the proximal portion, the expander apparatus is useful to positionthe distal portion without substantially disturbing the proximalportion.

In some procedures, an expander apparatus is used to further expand theskirt portion 24 towards the enlarged configuration (illustrated in FIG.4). The expander apparatus is inserted into the access device, andtypically has two or more members that are movable to engage theinterior wall of the skirt portion 24 and apply a force sufficient tofurther expand the skirt portion 24. FIGS. 16 and 17 show one embodimentof an expander apparatus 200 that has a first component 202 and a secondcomponent 204. The first component 202 and the second component 204 ofthe expander apparatus 200 are arranged in a tongs-like configurationand are pivotable about a pin 206. The first and second components 202and 204 can be constructed of steel having a thickness of about 9.7 mm.Each of the first and second components 202 and 204 has a proximalhandle portion 208 and a distal expander portion 210. Each proximalhandle portion 208 has a finger grip 212 that may extend transverselyfrom an axis, e.g., a longitudinal axis 214, of the apparatus 200. Theproximal handle portion 208 may further include a stop element, such asflange 216, that extends transversely from the longitudinal axis 214.The flange 216 preferably is dimensioned to engage the proximal end 25of the access device 20 when the apparatus 200 is inserted apredetermined depth. This arrangement provides a visual and tactileindication of the proper depth for inserting the expander apparatus 200.In one embodiment, a dimension 218 from the flange 216 to the distal tip220 is about 106 mm. The dimension 218 is determined by the length ofthe access device 20, which in turn is a function of the depth of thebody structures beneath the skin surface at which the surgical procedureis to be performed. The distal portions 210 are each provided with anouter surface 222 for engaging the inside wall of the skirt portion 24.The outer surface 222 is a frusto-conical surface in one embodiment. Theexpander apparatus 200 has an unexpanded distal width 224 at the distaltip 220 that is about 18.5 mm in one embodiment.

In use, the finger grips 212 are approximated towards one another, asindicated by arrows A in FIG. 17, which causes the distal portions 210to move to the enlarged configuration, as indicated by arrows B. Thecomponents 202 and 204 are also provided with a cooperating tab 226 andshoulder portion 228 which are configured for mutual engagement when thedistal portions 210 are in the expanded configuration. In theillustrated embodiment, the expander apparatus 200 has an expandeddistal width 230 that extends between the distal portions 210. Theexpanded distal width 230 can be about 65 mm or less, about as large as83 mm or less, or any other suitable width. The tab 226 and shoulderportion 228 together limit the expansion of the expander apparatus 200to prevent expansion of the skirt portion 24 of the access device 20beyond its designed dimension, and to minimize trauma to the underlyingtissue. Further features related to the expander apparatus are describedin U.S. Pat. No. 6,652,553, issued Nov. 25, 2003, which is incorporatedby reference in its entirety herein.

When the access device 20 is inserted into the patient and the outersleeve 32 is removed, the skirt portion 24 expands to a point where theoutward resilient expansion of the skirt portion 24 is balanced by theforce of the surrounding tissue. The surgical space defined by theaccess device 20 may be sufficient to perform any of a number ofsurgical procedures or combination of surgical procedures describedherein. However, if it is desired to expand the access device 20further, the expander apparatus 200, or a similar device, may beinserted into the access device 20 in the reduced profile configurationuntil the shoulder portions 216 are in approximation with the proximalend 25 of the skirt portion 24 of the access device 20, as shown in FIG.18.

FIG. 18 shows the expander apparatus 200 inserted in the access device20 in the reduced profiled configuration. Expansion of the expanderapparatus 200 is achieved by approximating the handle portions 212 (notshown in FIG. 18), which causes the distal portions 210 of the expanderapparatus 200 to move to a spaced apart configuration. As the distalportions 210 move apart and contact the inner wall of the skirt portion24, the rivet 44 is allowed to slide within the slots 46 and 48 of theskirt portion 24, thus permitting the skirt portion 24 to expand. Whenthe distal portions 210 reach the maximum expansion of the skirt portion24 (illustrated by a dashed line in FIG. 19), the tab 226 and shoulderportion 228 of the expander apparatus 200 come into engagement toprevent further expansion of the tongs-like portions (as illustrated inFIG. 17). Alternatively, the access device 20 may be expanded withanother device that can selectively have a reduced profile configurationand an expanded configuration, e.g., a balloon or similar device.

An optional step in the procedure is to adjust the location of thedistal portion of the access device 20 relative to the body structuresto be operated on. For example, the expander apparatus 200 may also beused to engage the inner wall of the skirt portion 24 of the accessdevice 20 in order to move the skirt portion 24 of the access device 20to the desired location. For an embodiment in which the skirt portion 24of the access device 20 is relatively movable relative to the proximalportion, e.g. by use of the rivet 30, the expander apparatus 200 isuseful to position the skirt portion 24 without substantially disturbingthe proximal portion 22 or the tissues closer to the skin surface of thepatient. As will be described below, the ability to move the distal endportion, e.g., the skirt portion 24, without disturbing the proximalportion is especially beneficial when an additional apparatus is coupledwith the proximal portion of the access device, as described below.

B. Systems and Devices for Stabilization and Visualization

Some procedures can be conducted through the access device 20 withoutany additional peripheral components being connected thereto. In otherprocedures it may be beneficial to provide at least one of a supportdevice and a viewing element. As discussed more fully below, supportdevices can be advantageously employed to provide support to peripheralequipment and to surgical tools of various types. Various embodiments ofsupport devices and viewing elements are discussed herein below.

1. Support Devices

One type of support device that can be coupled with the access device 20is a device that supports a viewing element. In one embodiment, anendoscope mount platform 300 and indexing arm 400 support an endoscope500 on the proximal end 25 of the access device 20 for remotely viewingthe surgical procedure, as illustrated in FIGS. 20-23. The endoscopemount platform 300 may also provide several other functions during thesurgical procedure. The endoscope mount platform 300 preferably includesa base 302 that extends laterally from a central opening 304 in agenerally ring-shaped configuration. In one application, the physicianviews the procedure primarily by observing a monitor, when insertingsurgical instruments into the central opening 304. The base 302advantageously enables the physician by providing a visual indicator (inthat it may be observable in the physician's peripheral vision) as wellas tactile feedback as instruments are lowered towards the centralopening 304 and into the access device 20.

The endoscope mount platform 300 preferably has a guide portion 306 at alocation off-set from the central opening 304 that extends substantiallyparallel to a longitudinal axis 308. The base 302 can be molded as onepiece with the guide portion 306. The base 302 and guide portion 306 maybe constructed with a suitable polymer, such as, for example,polyetheretherketone (PEEK).

The guide portion 306 includes a first upright member 310 that extendsupward from the base 302 and a second upright member 312 that extendsupward from the base 302. In one embodiment, the upright members 310,312 each have a respective vertical groove 314 and 315 that can slidablyreceive an endoscopic mount assembly 318.

The endoscope 500 (not shown in FIG. 20) can be movably mounted to theendoscope mount platform 300 with the endoscope mount assembly 318 inone embodiment. The endoscope mount assembly 318 includes an endoscopemount 320 and a saddle unit 322. The saddle unit 322 is slidably mountedwithin the grooves 314 and 315 in the upright members 310 and 312. Theendoscope mount 320 receives the endoscope 500 through a bore 326 whichpasses through the endoscope mount 320. Part of the endoscope 500 mayextend through the access device 20 substantially parallel tolongitudinal axis 308 into the patient's body 130, as shown in FIG. 25.

The endoscope mount 320 is removably positioned in a recess 328 definedin the substantially “U”-shaped saddle unit 322. In one embodiment, thesaddle unit 322 is selectively movable in a direction parallel to thelongitudinal axis 308 in order to position the endoscope 500 at thedesired height within the access device 20. The movement of theendoscope 500 by way of the saddle unit 322 also advantageously enablesthe physician to increase visualization of a particular portion of thesurgical space defined by the access device, e.g., by way of a zoomfeature, as required for a given procedure or a step of a procedure.

In one embodiment, an elevation adjustment mechanism 340, which may be ascrew mechanism, is positioned on the base 302 between the uprightmembers 310 and 312. The elevation adjustment mechanism 340 can be usedto selectively move a viewing element, e.g., the endoscope 500 by way ofthe saddle unit 322. In one embodiment, the elevation adjustmentmechanism 340 comprises a thumb wheel 342 and a spindle 344. The thumbwheel 343 is rotatably mounted in a bore in the base 302. The thumbwheel 342 has an external thread 346 received in a cooperating thread inthe base 302. The spindle 344 is mounted for movement substantiallyparallel to the central axis 308. The spindle 344 preferably has a firstend received in a rectangular opening in the saddle unit 322, whichinhibits rotational movement of the spindle 344. The second end of thespindle 344 has an external thread that cooperates with an internalthread formed in a bore within the thumb wheel 342. Rotation of thethumb wheel 342 relative to the spindle 344 causes relative axialmovement of the spindle unit 344 along with the saddle unit 322. Furtherdetails and features related to endoscope mount platforms are describedin U.S. Pat. Nos. 6,361,488, issued Mar. 26, 2002; 6,530,880, issuedMar. 11, 2003, and U.S. patent application Ser. No. 09/940,402, filedAug. 27, 2001, published as Publication No. 2003/0040656 on Feb. 27,2003, which are incorporated by reference in their entireties herein.

FIGS. 21-23 show that the endoscope mount platform 300 is mountable tothe support arm 400 in one embodiment. The support arm 400, in turn,preferably is mountable to a mechanical support, such as mechanicalsupport arm A, discussed above in connection with FIG. 1. The supportarm 400 preferably rests on, or is otherwise coupled with, the proximalend 25 of the access device 20. In one embodiment, the support arm 400is coupled with an indexing collar 420, which is configured to bereceived in the central opening 304 of the base 302 of endoscope mountplatform 300. The indexing collar 420 is substantially toroidal insection and has an outer peripheral wall surface 422, an inner wallsurface 424, and a wall thickness 426 that is the distance between thewall surfaces 422, 424. The indexing collar 420 further includes aflange 428, which supports the indexing collar 420 on the support arm400.

In one embodiment, a plurality of collars 420 may be provided to makethe surgical system 10 modular in that different access devices 20 maybe used with a single endoscope mount platform 300. For example, accessdevices 20 of different dimensions may be supported by providingindexing collars 420 to accommodate each access device size while usinga single endoscope mount platform 300. The central opening 304 of theendoscope mount platform 300 can have a constant dimension, e.g., adiameter of about 32.6 mm. An appropriate indexing collar 420 isselected, e.g., one that is appropriately sized to support a selectedaccess device 20. Thus, the outer wall 422 and the outer diameter 430are unchanged between different indexing collars 420, although the innerwall 424 and the inner diameter 432 vary to accommodate differentlysized access devices 20.

The indexing collar 420 can be positioned at or rested on the proximalportion of the access device 20 to allow angular movement of theendoscope mount platform 300 with respect thereto about the longitudinalaxis 308 (as indicated by an arrow C in FIG. 21). The outer wall 422 ofthe index collar 420 includes a plurality of hemispherical recesses 450that can receive one or more ball plungers 350 on the endoscope mountplatform 300 (indicated in dashed line). This arrangement permits theendoscope mount platform 300, along with the endoscope 500, to be fixedin a plurality of discrete angular positions. Further details andfeatures related to support arms and indexing collars are described inU.S. Pat. No. 6,361,488, issued Mar. 26, 2002, U.S. Pat. No. 6,530,880issued Mar. 11, 2003, and application Ser. No. 09/940,402 filed Aug. 27,2001, published as Publication No. 2003/0040656 on Feb. 27, 2003, whichare incorporated by reference in their entireties herein.

2. Viewing Elements

As discussed above, a variety of viewing elements and visualizationtechniques are embodied in variations of the surgical system 10. Oneviewing element that is provided in one embodiment is an endoscope.

FIG. 24 shows one embodiment of the endoscope 500 that has an elongatedconfiguration that extends into the access device 20 in order to enableviewing of the surgical site. In particular, the endoscope 500 has anelongated rod portion 502 and a body portion 504. The rod portion 502extends generally perpendicularly from the body portion 504. In oneembodiment, the rod portion 502 of endoscope 500 has a diameter of about4 mm and a length of about 106 mm. Body portion 504 may define a tubularportion 506 configured to be slidably received in the bore 326 ofendoscope mount 320 as indicated by an arrow D. The slidable mounting ofthe endoscope 500 on the endoscope mount platform 300 permits theendoscope 500 to adjust to access device configurations that havedifferent diameters. Additional mobility of the endoscope 500 in viewingthe surgical site may be provided by rotating the endoscope mountplatform 300 about the central axis 308 (as indicated by arrow C in FIG.21).

The rod portion 502 supports an optical portion (not shown) at a distalend 508 thereof. In one embodiment, the rod portion 502 defines a fieldof view of about 105 degrees and a direction of view 511 of about 25-30degrees. An eyepiece 512 preferably is positioned at an end portion ofthe body portion 504. A suitable camera (not shown) preferably isattached to the endoscope 500 adjacent the eyepiece 512 with a standardcoupler unit. A light post 510 can supply illumination to the surgicalsite at the distal end portion 508. A preferred camera for use in thesystem and procedures described herein is a three chip unit thatprovides greater resolution to the viewed image than a single chipdevice.

C. Apparatuses and Methods for Performing Spinal Procedures

The surgical assembly 10 described above can be deployed to perform awide variety of surgical procedures on the spine. In many cases, theprocedures are facilitated by inserting the access device andconfiguring it to provide greater access to a surgical location, asdiscussed above and by coupling the support arm 400 and the endoscopemount platform 300 with the proximal portion, e.g., on the proximal end25, of the access device 20 (FIGS. 1 and 22). As discussed above,visualization of the surgical location is enhanced by mounting a viewingelement, such as the endoscope 500, on the endoscope mount platform 300.Having established increased access to and visualization of the surgicallocation, a number of procedures may be effectively performed.

Generally, the procedures involve inserting one or more surgicalinstruments into the access device 20 to manipulate or act on the bodystructures that are located at least partially within the operativespace defined by the expanded portion of the access device 20. FIG. 25shows that in one method, the skirt portion 24 of access device 20 atleast partially defines a surgical site or operative space 90 in whichthe surgical procedures described herein may be performed. Dependingupon the overlap of the skirt portion, the skirt portion may define asurface which is continuous about the perimeter or which isdiscontinuous, having one or more gaps where the material of the skirtportion does not overlap.

One procedure performable through the access device 20, described ingreater detail below, is a two-level spinal fusion and fixation.Surgical instruments inserted into the access device may be used fordebridement and decortication. In particular, the soft tissue, such asfat and muscle, covering the vertebrae may be removed in order to allowthe physician to visually identify the various “landmarks,” or vertebralstructures, which enable the physician to determine the location forattaching a fastener, such a fastener 600, discussed below, or otherprocedures, as will be described herein. Enabling visual identificationof the vertebral structures enables the physician to perform theprocedure while viewing the surgical area through the endoscope,microscope, loupes, or other viewing element, or in a conventional, openmanner.

Tissue debridement and decortication of bone are completed using one ormore of a debrider blade, a bipolar sheath, a high speed burr, and anyother conventional manual instrument. The debrider blades are used toexcise, remove and aspirate the soft tissue. The bipolar sheath is usedto achieve hemostasis through spot and bulk tissue coagulation.Additional features of debrider blades and bipolar sheaths are describedin U.S. Pat. No. 6,193,715, assigned to Medical Scientific, Inc., whichis incorporated by reference in its entirety herein. The high speed burrand conventional manual instruments are also used to continue to exposethe structure of the vertebrae.

1. Fixation Systems and Devices

Having increased visualization of the pertinent anatomical structure,various procedures may be carried out on the structures. In oneprocedure, one or more fasteners are attached to adjacent vertebrae V.As discussed in more detail below, the fasteners can be used to providetemporary or permanent fixation and to provide dynamic stabilization ofthe vertebrae V. These procedures may combined with other procedures,such as procedures employing other types of implant, e.g., proceduresemploying fusion devices, prosthetic disc components, or other suitableimplants. In some procedures, fasteners are attached to the vertebraebefore or after fusion devices are inserted between the vertebrae V.Fusion systems and devices are discussed further below.

In one application, the desired location and orientation of the fasteneris determined before the fastener is applied to the vertebra. Thedesired location and orientation of the fastener may be determined inany suitable manner. For example, the pedicle entry point of the L5vertebrae may be located by identifying visual landmarks alone or incombination with lateral and A/P fluoroscopy, as is known in the art.With continued reference to FIG. 25, an entry point 92 into the vertebraV is prepared. In procedure, the entry point 92 may be prepared with anawl 550. The entry point 92 corresponds to the pedicle in one procedure.The entry point 92 may be prepared in any suitable manner, e.g.,employing a bone probe, a tap, and a sounder to create and verify theintegrity of the prepared vertebra. The sounder, as is known in the art,determines whether the hole that is made is surrounded by bone on allsides, and can be used to confirm that there has been no perforation ofthe pedicle wall.

After the hole in the pedicle beneath the entry point 92 is prepared, afastener may be advanced into the hole. Prior to advancing the fastener,or at any other point during the procedure, it may be desirable toadjust the location of the distal portion of the access device 20. Thedistal portion of the access device 20 may be adjusted by inserting theexpander apparatus 200 into the access device 20, expanding the distalportions 210, and contacting the inner wall of the skirt portion 24 tomove the skirt portion 24 to the desired location. This step may beperformed while the endoscope 500 is positioned within the access device20, and without substantially disturbing the location of the proximalportion of the access device 20 to which the endoscope mount platform300 may be attached.

FIGS. 26-27 illustrate one embodiment of a fastener 600 that isparticularly applicable in procedures involving fixation. The fastener600 preferably includes a screw portion 602, a housing 604, a spacermember 606, a biasing member 608, and a clamping member, such as a capscrew 610. The screw portion 602 has a distal threaded portion 612 and aproximal, substantially spherical joint portion 614. The threadedportion 612 is inserted into the hole that extends away from the entrypoint 92 into the vertebrae, as will be described below. Thesubstantially spherical joint portion 614 is received in a substantiallyannular, partly spherical recess 616 in the housing 604 in a ball andsocket joint relationship (see also FIG. 29).

As illustrated in FIG. 27, the fastener 600 is assembled by insertingthe screw portion 602 into a bore in a passage 618 in the housing 604until the joint portion 614 engages the annular recess 616. The screwportion 602 is retained in the housing 604 by the spacer member 606 andby the biasing member 608. The biasing member 608 provides a biasingforce to drive the spacer member 606 into frictional engagement with thejoint portion 614 of the screw member 602 and the annular recess 616 ofthe housing 604. The biasing provided by the biasing member 602frictionally maintains the relative positions of the housing 604 withrespect to the screw portion 602. The biasing member 608 preferably isselected such that biasing force prevents unrestricted movement of thehousing 604 relative to the screw portion 602. However, in someembodiments the biasing force is insufficient to resist the applicationof force by a physician to move the housing 604 relative to the screwportion 602. In other words, this biasing force is strong enoughmaintain the housing 604 stationary relative to the screw portion 602,but this force may be overcome by the physician to reorient the housing604 with respect to the screw member 602, as will be described below.

In the illustrated embodiment, the biasing member 608 is a resilientring having a gap 620, which permits the biasing member 608 to radiallycontract and expand. FIG. 27( a) illustrates that the biasing member 608may have an arched shape, when viewed end-on. The arched shape of thespring member 608 provides the biasing force, as will be describedbelow. The spacer member 606 and the biasing member 608 are insertedinto the housing 604 by radially compressing the biasing member into anannular groove 622 in the spacer member 606. The spacer member 606 andthe biasing member 608 are slid into the passage 618 until the distalsurface of the spacer member 606 engages the joint portion 614 of thescrew portion 602, and the biasing member 608 expands radially into theannular groove 622 in the housing 604. The annular groove 622 in thehousing 604 has a dimension 623 that is smaller than the uncompressedheight of the arched shape of the biasing member 608. When the biasingmember 608 is inserted in the annular groove 620, the biasing member 608is flattened against its normal bias, thereby exerting the biasing forceto the spacer member 606. It is understood that similar biasing members,such as coiled springs, belleville washers, or the like may be used tosupply the biasing force described herein.

The spacer member 606 is provided with a longitudinal bore 626, whichprovides access to a hexagonal recess 628 in the proximal end of thejoint portion 614 of the screw member 602. The proximal portion of thehousing 604 includes a pair of upright members 630 and 631 that areseparated by substantially “U”-shaped grooves 632. A recess forreceiving elongated member 650 is defined by the pair of grooves 632between upright members 630 and 631. Elongated member 650 preferably isconfigured to be placed distally into the housing 604 in an orientationsubstantially transverse to the longitudinal axis of the housing 604, aswill be described below. The inner walls of he upright members 630 and631 are provided with threads 634 for attachment of the cap screw 610 bythreads 613 therein.

Additional features of the fastener 600 are also described in U.S.patent application Ser. No. 10/075,668, filed Feb. 13, 2002, publishedas U.S. application Publication No. 2003/0153911A1 on Aug. 14, 2003, andapplication Ser. No. 10/087,489, filed Mar. 1, 2002, published as U.S.application Publication No. 2003/0167058A1 on Sep. 4, 2003, which areincorporated by reference in their entireties herein.

According to one application, the fastener 600 is inserted into theaccess device 20 and guided to the prepared hole at the entry point 92in the vertebrae. The fastener 600 preferably is simultaneouslysupported and advanced into the hole so that the fastener 600 is securedin the in the hole beneath the entry point 92. In the illustratedembodiment the fastener 600 is supported and attached to the bone by anendoscopic screwdriver apparatus 660, illustrated in FIGS. 28-29. Thescrewdriver 660 includes a proximal handle portion 662 (illustrated indashed line), an elongated body portion 664, and a distal tool portion666.

The distal tool portion 666, as illustrated in greater detail in FIG. 29includes a substantially hexagonal outer periphery that is received inthe substantially hexagonal recess 628 in the joint portion 614 of thescrew member 602. A spring member at the distal tool portion 666releasably engages the hexagonal recess 628 of the screw member 602 tosupport the fastener 600 during insertion and tightening. In theillustrated embodiment, a spring member 672 is configured to engage theside wall of the recess 628. More particularly, a channel or a groove isprovided in the tip portion 666 for receiving the spring member 672. Thechannel or groove includes a medial longitudinal notch portion 676, aproximal, angled channel portion 678, and a distal substantiallytransverse channel portion 680. The spring member 672 is preferablymanufactured from stainless steel and has a medial portion 682, proximalportion 684, and a transverse distal portion 686. The medial portion 682is partially received in the longitudinal notch portion 676. Theproximal portion 684 preferably is angled with respect to the medialportion 682 and is fixedly received in the angled channel portion 678.The transverse distal portion 686 preferably is slidably received in thetransverse channel 680. The medial portion 682 of the spring member 672is partially exposed from the distal tip portion 666 and normally isbiased in a transverse outward direction with respect to thelongitudinal axis (indicated by arrow E), in order to supply bearingforce against the wall of the recess 628. Alternatively, the distal tipportion of the screwdriver may be magnetized in order to hold the screwportion 602. Similarly, the distal tip portion may include a ballbearing or similar member which is normally biased in a radially outwarddirection to engage the interior wall of the recess 628 to secure thefastener 600 to the screwdriver distal tip 666. Other means may beprovided for temporarily but securely coupling the fastener 600 with thescrewdriver distal tip 666.

The insertion of the fastener 600 into the prepared hole that extendsinto the vertebrae from the entry point 92 may be achieved by insertionof screwdriver 660 into access device 20 (indicated by arrow G). Thisprocedure may be visualized by the use of the endoscope 500 inconjunction with fluoroscopy, or by way of any other suitable viewingelement. The screw portion 602 is threadedly advanced by the endoscopicscrewdriver 660 into the prepared hole that extends beneath the entrypoint 92 (indicated by arrow H). The endoscopic screwdriver 660 issubsequently separated from the fastener 600, by applying a force in theproximal direction, and thereby releasing the distal tip portion 666from the hexagonal recess 628 (e.g., causing the transverse distalportion 686 of the spring member 672 to slide within the transverserecess 680 against the bias, indicated by arrow F), and removing thescrewdriver 660 from the access device 20. An alternative method may usea guidewire, which is fixed in the hole beneath the entry point 92, anda cannulated screw which has an internal lumen and is guided over theguidewire into the hole beneath the entry point 92. Where a guidewiresystem is used, the screwdriver also would be cannulated so that thescrewdriver would fit over the guidewire.

For a two-level fixation, it may be necessary to prepare several holesand attach several fasteners 600. Preferably, the access device 20 issized to provide simultaneous access to all vertebrae in which thesurgical procedure is being performed. In some cases, however,additional enlargement or repositioning of the distal portion of theaccess device 20 may be helpful in providing sufficient access to theouter vertebrae, e.g., the L4 and S1 vertebrae. In the illustratedembodiment, the expander apparatus 200 may be repeatedly inserted intothe access device 20 and expanded in order to further open or toposition the skirt portion 24. In one procedure, additional fastenersare inserted in the L4 and S1 vertebrae in a similar fashion as thefastener 600 inserted into the L5 vertebra as described above. (Whendiscussed individually or collectively, a fastener and/or its individualcomponents will be referred to by the reference number, e.g., fastener600, housing 604, and all fasteners 600. However, when several fastenersand/or their components are discussed in relation to one another, analphabetic subscript will be used, e.g., fastener 600 a is moved towardsfastener 600 b.)

In one application, after the fasteners 600 are advanced into thevertebrae, the housing portions 604 of the fasteners 600 aresubstantially aligned such that their upright portions 630 and 631 faceupward, and the notches 632 are substantially aligned to receive theelongated member 650 therein. The frictional mounting of the housing 604to the screw member 602, described above, allows the housing 604 to betemporarily positioned until a subsequent tightening step is performed,described below.

Positioning of the housing portions 604 may be performed by the use ofan elongated surgical instrument capable of contacting and moving thehousing portion to the desired orientation. One such instrument forpositioning the housings 604 is a grasper apparatus 700, illustrated inFIG. 30. The grasper apparatus 700 includes a proximal handle portion702, an elongated body portion 704, and distal nose portion 706. Thedistal nose portion 706 includes a pair of grasping jaws 708 a and 708b, which are pivotable about pin 710 by actuation of the proximal handleportion 702. The grasping jaws 708 a and 708 b are illustrated in theclosed position in FIG. 30. Pivoting the movable handle 714 towardsstationary handle 712 causes longitudinal movement of actuator 716,which in turn pivots the jaw 708 b towards an open position (illustratedin dashed line). The biasing members 718 and 720 are provided to returnthe handles 712 and 714 to the open position and bias the jaws 708 a and708 b to the closed position.

In one application, the elongated member 650 is inserted into the accessdevice 20. In one application, the elongated member 650 is manufacturedfrom a biocompatible material and is sufficiently strong to maintain theposition of the vertebrae, or other body structures, coupled by theelongate member 650 with little or no relative motion therebetween. Inone embodiment, the elongated members 650 are manufactured from Titanium6/4 or titanium alloy. The elongated member 650 also may be manufacturedfrom stainless steel or any other suitable material. The transverseshape, width (e.g., radii), and lengths of the elongated members 650 areselected by the physician to provide the best fit for the positioning ofthe screw heads. Such selection may be performed by placing theelongated member 650 on the skin of the patient overlying the locationof the fasteners and viewed fluoroscopically. For example, a 70 mmpreformed rod having a 3.5″ bend radius may be selected for the spinalfixation.

In one application, the elongated member 650 is fixed to each of thefasteners 600, and more particularly, to the housings 604 of eachfastener 600. The grasper apparatus 700, described above, is alsoparticularly useful for inserting the elongated member 650 into theaccess device 20 and positioning it with respect to each housing 604. Asillustrated in FIG. 30, the jaws 708 a and 708 b of the grasperapparatus 700 each has shaped (e.g., curved) contact portions 722 a and722 b for contacting and holding the outer surface of the elongatedmember 650.

As illustrated in FIG. 31, the grasper apparatus 700 may be used toinsert the elongated member 650 into the operative space 90 defined atleast partially by the skirt portion 24 of the access device 20. In someembodiments, the cut-out portions 56 and 58 provided in the skirtportion 24 assist in the process of installing the elongated member 650with respect to the housings 604. The cut-out portions 56 and 58 allowan end portion 652 of the elongated member 650 to extend beyond theoperative space without raising or repositioning the skirt portion 24.The elongated member 650 is positioned within the recesses in eachhousing 604 defined by grooves 632 disposed between upright members 630and 631. The elongated member 650 is positioned in an orientationsubstantially transverse to the longitudinal axis of each housing 604.

Further positioning of the elongated member 650 may be performed byguide apparatus 800, illustrated in FIG. 32. Guide apparatus 800 isuseful in cooperation with an endoscopic screwdriver, such as endoscopicscrewdriver 660 (illustrated in FIG. 28), in order to position theelongated member 650, and to introduce and tighten the cap screw 610,described above and illustrated in FIG. 27. Tightening of the cap screw610 with respect to the housing 604 fixes the orientation of the housing604 with respect to the screw portion 602 and fixes the position of theelongated member 650 with respect to the housings 604.

In the illustrated embodiment, the guide apparatus 800 has a proximalhandle portion 802, an elongated body portion 804, and a distal toolportion 806. The elongated body portion 804 defines a central bore 808(illustrated in dashed line) along its longitudinal axis 810. Thecentral bore 808 is sized and configured to receive the endoscopicscrewdriver 660 and cap screw 610 therethrough. In the exemplaryembodiment, the diameter of the central bore 808 of the elongated bodyportion 804 is about 0.384-0.388 inches (9.75-9.86 mm) in diameter, andthe external diameter of the endoscopic screwdriver 660 (FIG. 28) isabout 0.25 inches (6.35 mm). The proximal handle portion 802 extendstransverse to the longitudinal axis 810, which allows the physician toadjust the guide apparatus 800 without interfering with the operation ofthe screwdriver 660.

The distal portion 806 of the apparatus includes several shaped cut outportions 814 which assist in positioning the elongated member 650. Asillustrated in FIG. 33, the cut out portions 814 are sized andconfigured to engage the surface of elongated member 650 and move theelongated member 650 from an initial location (illustrated in dashedline) to a desired location. In the illustrated embodiment, the cut outportions 814 are semicircular, to match the round elongated member 650.However, other shaped cut out portions may be provided to match othershaped elongated members.

As illustrated in FIG. 34, the guide apparatus 800 is used incooperation with the endoscopic screwdriver 660 to attach the cap screw610. The distal end of the body portion 804 includes a pair of elongatedopenings 816. The openings 816 provide a window to enable the physicianto endoscopically view the cap screw 610 retained at the distal tip 666of the endoscopic screw driver 660. Fewer or more than two openings canbe provided and the openings 816 need not be elongated.

The guide apparatus 800 and the endoscopic screwdriver 660 cooperate asfollows in one application. The guide apparatus 800 is configured to bepositioned in a surrounding configuration with the screwdriver 600. Inthe illustrated embodiment, the body portion 804 is configured forcoaxial placement about the screwdriver 660 in order to distribute thecontact force of the guide apparatus 800 on the elongated member 650.The distal portion 806 of the guide apparatus 800 may bear down on theelongated member 650 to seat the elongated member 650 in the notches 632in the housing 604. The “distributed” force of the guide apparatus 800may contact the elongated member 650 on at least one or more locations.In addition, the diameter of central bore 808 is selected to bemarginally larger than the exterior diameter of cap screw 610, such thatthe cap screw 610 may freely slide down the central bore 808, whilemaintaining the orientation shown in FIG. 34. This configuration allowsthe physician to have effective control of the placement of the capscrew 610 into the housing 604. The cap screw 610 is releasably attachedto the endoscopic screwdriver 660 by means of spring member 672 engagedto the interior wall of hexagonal recess 611 as it is inserted withinthe bore 808 of the body portion 804 of guide apparatus 800. The capscrew 610 is attached to the housing 604 by engaging the threads 615 ofthe cap screw 610 with the threads 634 of the housing.

As illustrated in FIG. 35, tightening of the cap screw 610 fixes theassembly of the housing 604 with respect to the elongated member 650. Inparticular, the distal surface of the cap screw 610 provides a distalforce against the elongated member 650, which in turn drives the spacermember 606 against the joint portion 614 of the screw portion 602, whichis fixed with respect to the housing 604.

If locations of the vertebrae are considered acceptable by thephysician, then the fixation procedure is substantially complete oncethe cap screws 610 have been attached to the respective housings 604,and tightened to provide a fixed structure as between the elongatedmember 650 and the various fasteners 600. However, if compression ordistraction of the vertebrae with respect to one another is requiredadditional apparatus would be used to shift the vertebrae prior to finaltightening all of the cap screws 610.

In the illustrated embodiment, this step is performed with a surgicalinstrument, such as a compressor-distracter instrument 900, illustratedin FIG. 36, which is useful to relatively position bone structures inthe cephcaudal direction and to fix their position with respect to oneanother. Thus, the compressor-distracter instrument 900 has thecapability to engage two fasteners 600 and to space them apart whilesimultaneously tightening one of the fasteners to fix the spacingbetween the two vertebrae, or other bone structures. Moreover, thecompressor-distracter instrument 900 may also be used to move twofasteners 600, and the vertebrae attached thereto into closerapproximation and fix the spacing therebetween.

The distal tool portion 902 of one embodiment of thecompressor-distracter instrument 900 is illustrated in FIG. 36. Thedistal tool portion 902 includes a driver portion 904 and a spacingmember 906. The driver portion 904 has a distal end portion 908 with aplurality of wrenching flats configured to engage the recess 611 in theproximal face of the cap screw 610, and to apply torque to the capscrew. The driver portion 904 is rotatable about the longitudinal axis(indicated by arrow M) to rotate the cap screw 610 relative to thefastener 600. Accordingly, the driver portion 904 can be rotated toloosen the cap screw 610 on the fastener 600 and permit movement of theelongated member 650 connected with the vertebra relative to thefastener 600 connected with the vertebra. The cap screw 610 can also berotated in order to tighten the cap screw 610 and clamp the elongatedmember 650 to the fastener 600.

The distal tool portion 902 may also include a spacing member, such asspacing member 906, which engages an adjacent fastener 600 b whiledriver member 904 is engaged with the housing 604 a to move the fastener600 b with respect to the fastener 600 a. In the exemplary embodiment,spacing member 906 comprises a jaw portion that is pivotably mounted tomove between a first position adjacent the driver portion and a secondposition spaced from the driver portion, as shown in FIG. 36. The distaltip 910 of the spacing member 906 is movable relative to the driverportion 904 in a direction extending transverse to the longitudinalaxis. (Further details and features related to compressor-distracterapparatuses are described in U.S. application Ser. No. 10/178,875, filedJun. 24, 2002, entitled “SURGICAL INSTRUMENT FOR MOVING VERTEBRAE,”published as U.S. patent application Publication No. 2003/0236529A1 onDec. 25, 2003, which is incorporated by reference in its entiretyherein. Also, further details and features related to other apparatusesfor manipulating implants and bone segments (e.g., vertebrae) to whichimplants are coupled are described in U.S. Pat. No. 6,648,888, issuedNov. 18, 2003, entitled “SURGICAL INSTRUMENT FOR MOVING VERTEBRAE.”)

As illustrated in FIG. 36, the spacer member 906 can be opened withrespect to the driver portion 904 to space the vertebrae farther apart(as indicated by arrow N). The distal portion 910 of the spacer member906 engages the housing 604 b of fastener 600 b and moves fastener 600 bfurther apart from fastener 600 a to distract the vertebrae. Where thevertebrae are to be moved closer together, e.g. compressed, the spacermember 906 is closed with respect to the driver portion 904 (arrow P),as illustrated in FIG. 37. The distal portion 910 of the spacer member906 engages the housing 604 b of the fastener 600 b and moves thefastener 600 b towards the fastener 600 a. When the spacing of thevertebrae is acceptable to the physician, the cap screw 610 a istightened by the driver member 904, thereby fixing the relationship ofthe housing 604 a with respect to the elongated member 650, and therebyfixing the position of the vertebrae, or other bone structures, withrespect to one another. In one application, once the elongated member650 is fixed with respect to the fasteners 600, the fixation portion ofthe procedure is substantially complete.

2. Fusion Systems and Devices

Although fixation may provide sufficient stabilization, in some cases itis also desirable to provide additional stabilization. For example,where one or more discs has degraded to the point that it needs to bereplaced, it may be desirable to position an implant, e.g., a fusiondevice, a prosthetic disc, a disc nucleus, etc., in the intervertebralspace formerly occupied by the disc.

In one application, a fusion device is inserted between adjacentvertebrae V. Portions of the fusion procedure can be performed before,during, or after portions of the fixation procedure. FIGS. 38-42illustrate one embodiment of a fusion device, referred to herein as aspinal implant 2010, that is inserted between adjacent vertebrae. Thespinal implant 2010 preferably is placed between adjacent vertebrae toprovide sufficient support to allow fusion of the adjacent vertebrae, asshown in FIGS. 48-49. The spinal implants 2010 are preferably made froman allograft material, though other materials could also be used,including autograft, xenograft, or some non-biologic biocompatiblematerial, such as titanium or stainless steel. Also, where non-biologicmaterials are used, the implant 2010 may be configured as a cage orother suitable configuration.

The spinal implant 2010 (FIGS. 38-42) has a first end 2020 for insertionbetween adjacent vertebrae V. The first end 2020 has a tapered surface2022 to facilitate insertion of the implant between adjacent vertebraeV. The surface 2022 defines an angle X of approximately 45° as shown inFIG. 41.

The spinal implant 2010 (FIGS. 38-39) has a second end 2030 that isengageable with a tool 2032 (FIG. 51) for inserting the implant betweenthe adjacent vertebrae V. The tool 2032 has a pair of projections 2034,one of which is shown in FIG. 51, that extend into recesses 2036 and2038 in the end 2030 of the implant 2010. The recesses 2036 and 2038(FIGS. 38-39) extend from the second end 2030 toward the first end 2020.The recess 2036 (FIG. 41) is defined by an upper surface 2040 and alower surface 2042 extending generally parallel to the upper surface2040. The recess 2038 (FIG. 39) has a lower surface 2046 and an uppersurface 2048. The upper surface 2048 extends generally parallel to thelower surface 2046.

The recesses 2036 and 2038 define a gripping portion 2052. Theprojections 2034 on the tool 2032 extend into the recesses 2036 and 2038and grip the gripping portion 2052. The projections 2034 engage theupper and lower surfaces 2040 and 2042 of the recess 2036 and the upperand lower surfaces 2046 and 2048 of the recess 2038. Accordingly, thetool 2032 can grip the implant 2010 for inserting the implant betweenthe adjacent vertebrae V.

As viewed in FIGS. 38-41, the implant 2010 has an upper surface 2060 forengaging the upper vertebra V. The implant 2010 has a lower surface2062, as viewed in FIGS. 38-41, for engaging the lower vertebra V. Theupper and lower surfaces 2060 and 2062 extend from the first end 2020 tothe second end 2030 of the implant 2010 and parallel to the upper andlower surfaces 2040, 2042, 2046, and 2048 of the recesses 2036 and 2038.The upper surface 2060 has teeth 2064 for engaging the upper vertebra V.The lower surface 2062 has teeth 2066 for engaging the lower vertebra V.Although FIGS. 38-39 show four teeth 2064 and four teeth 2066, it iscontemplated that any number of teeth could be used.

A first side surface 2070 and a second side surface 2072 extend betweenthe upper and lower surfaces 2060 and 2062. The first side surface 2070extends along a first arc from the first end 2022 of the implant 2010 tothe second end 2030. The second side surface 2072 extends along a secondarc from the first end 2022 to the second end 2030. The first and secondside surfaces 2070 and 2072 are concentric and define portions ofconcentric circles. The teeth 2064 and 2066 extend parallel to eachother and extend between the side surfaces 2070 and 2072 and alongsecant lines of the concentric circles defined by the side surfaces.

The implant 2010 preferably is formed by harvesting allograft materialfrom a femur, as known in the art. The femur is axially cut to formcylindrical pieces of allograft material. The cylindrical pieces arethen cut in half to form semi-cylindrical pieces of allograft material.The semi-cylindrical pieces of allograft material are machined into thespinal implants 2010.

A pair of spinal implants 2010 may be placed bilaterally between theadjacent vertebrae V. The access device 20 is positioned in thepatient's body adjacent the vertebrae V. The skirt portion 24 of theaccess device 20 preferably is in a radially expanded condition toprovide a working space adjacent the vertebrae V as described above.Disc material between the vertebrae V can be removed using instrumentssuch as kerrisons, rongeurs, or curettes. A microdebrider may also beutilized to remove the disc material. An osteotome, curettes, andscrapers can be used to prepare end plates of the vertebrae V forfusion. Preferably, an annulus of the disc is left between the vertebraeV.

Distracters can be used to sequentially distract the disc space untilthe desired distance between the vertebrae V is achieved. The fusiondevice or implant 2010 is placed between the vertebrae V using the tool2032. The first end 2020 of the implant 2010 is inserted first betweenthe vertebrae V. The implant 2010 is pushed between the vertebrae Vuntil the end 2030 of the implant is between the vertebrae. A secondspinal implant 2010 is inserted on the ipsilateral side using the sameprocedure.

A shield apparatus 3100 with an elongated portion 3102 may be used tofacilitate insertion of the implants 2010 between the vertebrae V. Adistal portion 3110 of the apparatus 3100 may be placed in anannulotomy. The implant 2010 is inserted with the side surface 2170facing the elongated portion 3102 so that the apparatus 3100 can act asa “shoe horn” to facilitate or guide insertion of the implants 2010between the vertebrae.

The implants 2010 may be inserted between the vertebrae V with the firstends 2020 located adjacent each other and the second ends 2030 spacedapart from each other, as shown in FIG. 48. The implants 2010 may alsobe inserted between the vertebrae V with the first ends 2020 of theimplants 2010 spaced apart approximately the same distance that thesecond ends 2030 are spaced apart. It is contemplated that the implants2010 may be inserted in any desired position between the vertebrae V. Itis also contemplated that in some embodiments only one implant 2010 maybe inserted between the vertebrae V. Furthermore, it is contemplatedthat the implants 2010 may be inserted between vertebrae using an openprocedure.

Another embodiment of a fusion device or spinal implant 2110 isillustrated in FIGS. 43-47. The spinal implant 2110 is substantiallysimilar to the embodiment disclosed in FIGS. 38-42. The implant 2110 isplaced between the adjacent vertebrae V to provide sufficient support toallow fusion of the adjacent vertebrae, as shown in FIG. 50. The spinalimplant 2110 is preferably made from an allograft material, though thematerials described above in connection with the spinal implant 2010 mayalso be used. Also, as with the implant 2010, the implant 2110 may beformed as a cage or other suitable configuration.

The spinal implant 2110 (FIGS. 43-47) has a first end 2120 for insertionbetween the adjacent vertebrae V. The first end 2120 has a taperedsurface 2122 to facilitate insertion of the implant between the adjacentvertebrae V. The surface 2122 defines an angle Y of approximately 45° asshown in FIG. 65.

The spinal implant 2110 (FIGS. 43-44) has a second end 2130 that isengageable with the projections 2034 on the tool 2032 for inserting theimplant between the adjacent vertebrae V. The projections 2034 extendinto recesses 2136 and 2138 in the end 2130 of the implant 2110. Therecesses 2136 and 2138 extend from the second end 2130 toward the firstend 2120. The recess 2136 (FIGS. 43 and 46) is defined by an uppersurface 2140 and a lower surface 2142 extending generally parallel tothe upper surface 2140. The recess 2138 (FIG. 44) has a lower surface2146 and an upper surface 2148 extending generally parallel to the lowersurface 2146.

The recesses 2136 and 2138 define a gripping portion 2152. Theprojections 2034 on the tool 2032 extend into the recesses 2136 and 2138and grip the gripping portion 2152. The projections 2034 engage theupper and lower surfaces 2140 and 2142 of the recess 2136 and the upperand lower surfaces 2146 and 2148 of the recess 2138. Accordingly, thetool 2032 can grip the implant 2110 for inserting the implant betweenthe adjacent vertebrae V.

As viewed in FIGS. 43-46, the implant 2110 has an upper surface 2160 forengaging the upper vertebra V. The implant 2110 has a lower surface2162, as viewed in FIGS. 43-46, for engaging the lower vertebra V. Theupper and lower surfaces 2160 and 2162 extend from the first end 2120 tothe second end 2130 of the implant 2110 and parallel to the upper andlower surfaces 2140, 2142, 2146, and 2148 of the recesses 2136 and 2138.The upper surface 2160 has teeth 2164 for engaging the upper vertebra V.The lower surface 2162 has teeth 2166 for engaging the lower vertebra V.Although FIG. 44 shows four teeth 2164 and four teeth 2166, it iscontemplated that any number of teeth could be used.

A first side surface 2170 and a second side surface 2172 extend betweenthe upper and lower surfaces 2160 and 2162. The first side surface 2170extends along a first arc from the first end 2122 of the implant 2110 tothe second end 2130. The second side surface 2172 extends along a secondarc from the first end 2120 to the second end 2130. The first and secondside surfaces 2170 and 2172 are concentric and define portions ofconcentric circles. The teeth 2164 and 2166 extend parallel to eachother and between the side surfaces 2170 and 2172 along secant lines ofthe concentric circles defined by the side surfaces.

The implant 2110 preferably is formed by harvesting allograft materialfrom a femur, as is known in the art. The femur is axially cut to formcylindrical pieces of allograft material. The cylindrical pieces arethen cut in half to form semi-cylindrical pieces of allograft material.The semi-cylindrical pieces of allograft material are machined into thespinal implants 2110.

A spinal implant 2110 is placed unilaterally between the adjacentvertebrae V. The access device 20 is positioned in the patient's bodyadjacent the vertebrae V. The skirt portion 24 of the access device 20preferably is in a radially expanded condition to provide a workingspace adjacent the vertebrae V as described above. Disc material betweenthe vertebrae V can be removed using instruments such as kerrisons,rongeurs, or curettes. A microdebrider may also be utilized to removethe disc material. An osteotome, curettes, and scrapers can be used toprepare end plates of the vertebrae V for fusion. Preferably, an annulusof the disc is left between the vertebrae V.

Distracters are used to sequentially distract the disc space until thedesired distance between the vertebrae V is achieved. The implant 2110is placed between the vertebrae V using the tool 2032. It iscontemplated that the apparatus 3100 could be used also. The first end2120 of the implant 2110 is inserted first between the vertebrae V. Theimplant 2110 is pushed between the vertebrae V until the end 2130 of theimplant is between the vertebrae. It is contemplated that the implant2110 may be inserted in any desired position between the vertebrae V. Itis also contemplated that in some embodiments more than one implant 2110may be inserted between the vertebrae.

The apparatus or shield 3100 for use in placing the fusion devices orspinal implants between the vertebrae is illustrated in FIGS. 52-56. Theapparatus 3100 preferably includes an elongated body portion 3102, whichprotects the nerve root or dura, and a mounting portion 3104, whichallows for the surgeon to releasably mount the apparatus 3100 to theaccess device 20. Consequently, the surgeon is able to perform thesurgical procedures without requiring the surgeon or an assistant tocontinue to support the apparatus 3100 throughout the procedure, andwithout reducing the field of view.

The apparatus 3100 may be manufactured from a biocompatible materialsuch as, for example, stainless steel. In the illustrated embodiment,apparatus 3100 is manufactured from stainless steel having a thicknessof about 0.02 inches (0.508 mm) to about 0.036 inches (0.914 mm). Theelongated body portion 3102 has dimensions that correspond to the depthin the body in which the procedure is being performed, and to the sizeof the body structure that is to be shielded by elongated body portion3102. In the exemplary embodiment, the elongated body portion 3102 has awidth 3106 of about 0.346 inches (8.79 mm) and a length of about 5.06inches (128.5 mm) (FIG. 53), although other dimensions would beappropriate for spinal surgical procedures performed at differentlocations, or for surgical procedures involving different bodystructures. The distal tip portion 3110 of the apparatus 3100 may have aslightly curved “bell mouth” configuration which allows for atraumaticcontact with a body structure, such as a nerve. It is contemplated thatthe elongated body portion may have any desired shape.

The mounting portion 3104 preferably allows the apparatus 3100 to besecured to a support structure in any number of ways. In the exemplaryembodiment, mounting portion 3104 may include a ring portion. Withreference to FIGS. 52-56, ring portion 3120 has a substantiallyring-shaped configuration with an opening 3124, which defines an angle3126 of about 90 degrees of the total circumference of the ring portion3120. As will be described in greater detail below, the angle 3126 is anominal value, because the ring portion 3104 is resilient, which permitsthe opening 3124 to change size during the mounting process.

In the illustrated embodiment, the mounting portion 3104 has asubstantially cylindrical configuration in order to be mounted withinthe interior lumen of the access device 20, as will be described below.The ring portion 3104 has an exterior dimension 3130 of about 0.79inches (20.1 mm), and an interior dimension 3132 of about 0.76 inches(19.3 mm). It is understood that the dimensions of the ring portion 3104can be different, such as, for example, where the access device 20 has adifferent interior dimension. Moreover, the cylindrical shape of thering portion 3104 can change, such as, for example, where the apparatus3100 is used with a support member having a differently shaped internallumen.

Finger grip portions 3122 preferably extend from the mounting portion3104 and allow the surgeon to apply an inwardly directed force (asindicated by arrows A) to the ring portion 3120. The resilientcharacteristics of the ring portion 3120 allow the material to deflectthereby reducing the exterior dimension 3130 and reducing the spacing3124. Releasing the finger grip portions 3122 allows the ring portion tomove towards its undeflected condition, thereby engaging the interiorwall of the access device 20.

The elongated body portion 3102 and the mounting portion 3104 may bemanufactured from a single component, such as a sheet of stainlesssteel, and the mounting portion 3104 may be subsequently formed into asubstantially cylindrical shape. In another embodiment, the mountingportion 3104 may be manufactured as a separate component and coupledwith the elongated body portion, by techniques such as, for example,welding and/or securement by fasteners, such as rivets.

The access device 20 serves as a stable mounting structure for apparatus3100. In particular, mounting portion 3104 is releasably mounted to theinterior wall of proximal wall portion 22 of access device 20. Elongatedbody portion 3102 extends distally into the operative site to protectthe desired body structure, such as the nerve, as will be describedbelow.

To install the apparatus 3100 within the interior passage of theproximal wall portion 22, the surgeon may apply an inwardly directedforce on the ring portion 3120, thereby causing the ring portion toresiliently deform, as illustrated by dashed line and arrows B in FIG.59. The surgeon subsequently inserts the apparatus 3100 into theinterior lumen of the proximal wall portion 22 (as indicated by arrow C)to the position of ring portion 3104 illustrated in solid line in FIG.58. When the surgeon releases the finger grip portions 3122, the ringportion 3120 resiliently moves towards its undeflected configuration,thereby engaging the interior lumen of the proximal wall portion 22.Advantages of some embodiments include that the mounting portion 3104 iseasily removed and/or moved with respect to the access device 20 withoutdisturbing the position of the access device 20 or any otherinstrumentation.

As illustrated in FIG. 57, the configuration of the mounting portion3104 and the elongated body portion 3102 allow the elongated bodyportion to occupy a small space along the periphery of the proximal wallportion 3122. This allows the apparatus to protect the desired bodystructure without blocking access for the insertion of other surgicalinstrumentation, and without blocking visibility by the surgeon duringthe procedure.

The mounting portion 3104 is one exemplary configuration for mountingthe apparatus 3100 to the support structure. It is contemplated that theapparatus 3100 may be mounted within the access device 20 in anysuitable manner.

When in position, the distal end portion 3110 covers the exiting nerveroot R, while exposing the disc annulus A (See FIG. 57). As discussedabove, the debridement and decortication of tissue covering thevertebrae, as well as a facetectomy and/or laminectomy if indicated, arepreferably performed prior to the insertion of apparatus 3100 into thesurgical space. Accordingly, in some embodiments, there is no need todisplace or retract tissue, and apparatus 3100 merely covers the nerveroot and does not substantially displace the nerve root or any otherbody tissue. It is understood that the term “cover” as used hereinrefers to apparatus 3100 being adjacent to the body structure, or incontact with the body structure without applying significant tension ordisplacement force to the body structure.

Additional surgical instrumentation S may be inserted into the accessdevice to perform procedures on the surrounding tissue. For example, anannulotomy may be performed using a long handled knife and kerrisons. Adiscectomy may be completed by using curettes and rongeurs. Removal ofosteophytes which may have accumulated between the vertebrae may beperformed using osteotomes and chisels.

As illustrated in FIG. 60, the elongated body portion 3102 preferably isrotated to protect the spinal cord, or dura D, during the aboveprocedures. The surgeon may change the position of the apparatus 3100 byapproximating the finger grips 3122 to release the ring portion fromengagement with the inner wall of the proximal wall portion 20, and thenre-position the apparatus 3100 without disturbing the access device 20(as shown in FIG. 58).

During certain surgical procedures, it may be useful to introducecrushed bone fragments or the fusion devices 2010 or 2110 to promotebone fusion. As illustrated in FIGS. 61-62, apparatus 3100 is useful todirect the implants into the space I between adjacent vertebrae V. Asshown in the figures, the distal portion 3110 of the elongated bodyportion 3102 is partially inserted into the space I. The distal endportion 3110, is positioned between adjacent vertebrae V, and creates apartially enclosed space for receiving the implants or other materialtherein.

Another embodiment of the apparatus or shield is illustrated in FIGS.63-64, and designated apparatus 3200. Apparatus 3200 is substantiallyidentical to apparatus 3100, described above, with the followingdifferences noted herein. In particular, distal end portion 3210includes a pair of surfaces 3240 and 3242. Surface 3240 is an extensionof elongated shield portion 3202, and surface 3242 extends at an anglewith respect to surface 3240. In the exemplary embodiment, surfaces 3240and 3242 defined an angle of about 90 degrees between them.Alternatively another angle between surfaces 3240 and 3242 may bedefined as indicated by the body structures to be protected.

Distal end portion 3210 allows the apparatus to provide simultaneousshielding of both the dura D and the nerve root R. In FIGS. 65-66,surface 3242 shields the dura D, and surface 3240 shields the nerve rootR. It is understood that surfaces 3240 and 3242 may be interchanged withrespect to which tissue they protect during the surgical procedure.

According to the exemplary embodiment, once the fusion and fixationportions of the procedure have been performed, the procedure issubstantially complete. The surgical instrumentation, such as theendoscope 500 can be withdrawn from the surgical site. The access device20 is also withdrawn from the site. The muscle and fascia typicallyclose as the access device 20 is withdrawn through the dilated tissuesin the reduced profile configuration. The fascia and skin incisions areclosed in the typical manner, with sutures, etc. The procedure describedabove may be repeated for the other lateral side of the same vertebrae,if indicated.

II. Surgical Procedures that May be Performed with the Systems DescribedHerein

As discussed above, the systems disclosed herein provide access to asurgical location at or near the spine of a patient to enable procedureson the spine. These procedures can be applied to one or more vertebrallevels, as discussed above. Additional procedures and combinations ofprocedures that may be performed using the systems described herein arediscussed below. In various forms, these procedures involve an anteriorlumbar interbody fusion, a minimally invasive lumbar interbody fusion,and other procedures particularly enabled by the access devices andsystems described above.

A. Procedures Involving Anterior Lumbar Interbody Fusion

The access devices and systems described herein are amenable to avariety of procedures that may be combined with an anterior lumbarinterbody fusion (referred to herein as an “ALIF”).

In one embodiment of a first method, three adjacent vertebrae, such asthe L4, the L5, and the S1 vertebrae of the spine, are treated by firstperforming an ALIF procedure. Such a procedure may be performed in aconvention manner. The ALIF involves exposing a portion of the spine, inparticular the vertebrae and discs located in the interbody spaces,i.e., the spaces between adjacent vertebrae. Any suitable technique forexposing the interbody spaces may be employed, e.g., an open, mini-open,or minimally invasive procedure. In one embodiment, the interbody spacesbetween the L4, L5, and S1 vertebrae are exposed to the surgeon. Onceexposed, the surgeon may prepare the interbody space, if needed, in anysuitable manner. For example, some or all of the disc may be removedfrom the interbody space and the height of the interbody space may beincreased or decreased. The interbody space between the L4 and the L5vertebrae may be exposed separately from the interbody space between theL5 and S1 vertebrae or they may be generally simultaneously exposed andprepared.

After the interbody space has been exposed and prepared, a suitablefusion procedure may be performed. For example, in one example fusionprocedure, one or more fusion devices may be placed in the interbodyspace. Any suitable fusion device may be used, e.g., a fusion cage, afemoral ring, or another suitable implant. Various embodiments ofimplants and techniques and tools for the insertion of implants aredescribed in U.S. application Ser. No. 10/280,489, filed Oct. 25, 2002,which has been published as Publication No. 2003/0073998 on Apr. 17,2003, which is hereby incorporated by reference herein in its entirety.In one variation, one or more fusion cages may be placed in an interbodyspace, e.g., between the L4 and L5 vertebrae, between the L5 and S1vertebrae, or between the L4 and L5 vertebrae and between the L5 and S1vertebrae. In another variation, one or more femoral rings may besubstituted for one or more of the fusion cages and placed between theL4 and L5 vertebrae and/or between the L5 and S1 vertebrae. In anothervariation, one or more fusion devices are combined with a bone growthsubstance, e.g., bone chips, to enhance bone growth in the interbodyspace(s).

After anterior placement of the fusion device, an access device isinserted into the patient to provide access to a spinal location, asdescribed above. A variety of anatomical approaches may be used toprovide access to a spinal location using the access device 20. Theaccess device preferably is inserted generally posteriorly. As usedherein the phrase “generally posteriorly” is used in its ordinary senseand is a broad term that refers to a variety of surgical approaches tothe spine that may be provided from the posterior side, i.e., the back,of the patient, and includes, but is not limited to, posterior,postero-lateral, and transforaminal approaches. Any of the accessdevices described or incorporated herein, such as the access device 20,could be used.

The distal end of the access device may be placed at the desiredsurgical location, e.g., adjacent the spine of the patient with acentral region of the access device over a first vertebrae. In oneprocedure, the distal end of the access device is inserted until itcontacts at least a portion of at least one of the vertebrae beingtreated or at least a portion of the spine. In another procedure, thedistal end of the access device is inserted until it contacts a portionof the spine and then is withdrawn a small amount to provide a selectedgap between the spine and the access device. In other procedures, theaccess device may be inserted a selected amount, but not far enough tocontact the vertebrae being treated, the portion of the vertebrae beingtreated, or the spine.

The access device may be configured, as described above, to provideincreased access to the surgical location. The access device can have afirst configuration for insertion to the surgical location over thefirst vertebra and a second configuration wherein increased access isprovided to the adjacent vertebrae. The first configuration may providea first cross-sectional area at a distal portion thereof. The secondconfiguration may provide a second cross-sectional area at the distalportion thereof. The second cross-sectional area preferably is enlargedcompared to the first cross-sectional area. In some embodiments, theaccess device may be expanded from the first configuration to the secondconfiguration to provide access to the adjacent vertebrae above andbelow the first vertebra.

When it is desired to treat the L4, L5, and S1 vertebrae, the accessdevice may be inserted over the L5 vertebrae and then expanded toprovide increased access to the L4 and S1 vertebrae. In one embodiment,the access device can be expanded to an oblong shaped configurationwherein the access device provides a first dimension of about 63 mm, anda second dimension perpendicular to the first dimension of about 24 mm.In another embodiment, the access device can be expanded to provide afirst dimension of about 63 mm, and a second dimension perpendicular tothe first dimension of about 27 mm. These dimensions provide a surgicalspace that is large enough to provide access to at least three adjacentvertebrae without exposing excessive amounts of adjacent tissue that isnot required to be exposed for the procedures being performed. Otherdimensions and configurations are possible that would provide the neededaccess for procedures involving three adjacent vertebrae.

When the access device is in the second configuration, fixation of thethree vertebrae may be performed. As discussed above, fixation is aprocedure that involves providing a generally rigid connection betweenat least two vertebrae. Any of the fixation procedures discussed abovecould be used in this method, as could other fixation procedures. Onefixation procedure that could be used is discussed above in connectionwith FIG. 36 wherein the fasteners 600 a, 600 b, and 600 c are advancedthrough the access device 20 to three adjacent vertebrae and areattached to the vertebrae. The three fasteners 600 a, 600 b, and 600 care interconnected by the elongated member 650. The three fasteners 600a, 600 b, and 600 c and the elongate member 650 comprise a firstfixation assembly. A second fixation assembly may be applied to thepatient on the opposite side of the spine, i.e., about the same locationon the opposite side of the medial line of the spine. Other fixationprocedures could be applied, e.g., including two fasteners that coupledwith the L4 and the S1 vertebrae and an elongate member interconnectingthese vertebrae.

One variation of the first method provides one level of fixation on theanterior side of the patient, e.g., when the fusion device is placed inthe interbody space. For example, fixation of the L5 and S1 vertebraecould be provided on the anterior side of the spine, in addition to theother procedures set forth above (e.g., a two level postero-lateralfixation). Also, fixation of the L4 and L5 vertebrae could be providedon the anterior side of the spine, in addition to the other proceduresset forth above (e.g., a two level postero-lateral fixation).

In a second method, substantially the same steps as set forth above inconnection with the first method would be performed. In addition, afterthe access device is inserted, a decompression procedure is performedthrough the access device. A decompression procedure is one whereunwanted bone is removed from one or more vertebrae. Unwanted bone caninclude stenotic bone growth, which can cause impingement on theexisting nerve roots or spinal cord. Decompression procedures that maybe performed include laminectomy, which is the removal of a portion of alamina(e), and facetectomy, which is the removal of a portion of one ormore facets. In one variation of this method, decompression includesboth a facetectomy and a laminectomy. Any suitable tool may be used toperform decompression. One tool that is particularly useful is akerrison.

In a third method, substantially the same steps as set forth above inconnection with the first method would be performed. That is, an ALIFprocedure is performed in combination with a fixation procedure. Inaddition, a fusion procedure may be performed through the access devicewhich may have been placed generally posteriorly, e.g.,postero-laterally, tranforaminally or posteriorly, whereby bone growthis promoted between the vertebrae and the fixation assembly, includingat least one of the fasteners 600 a, 600 b, 600 c and/or the elongateelement 650. This procedure is also referred to herein as an “externalfusion” procedure.

One example of an external fusion procedure that may be performedinvolves placement of a substance through the access device intended toencourage bone growth in and around the fixation assembly. Thus, fusionmay be enhanced by placing a bone growth substance adjacent any of thefasteners 600 a, 600 b, 600 c and/or the elongate member 650. The bonegrowth substance may take any suitable form, e.g., small bone chipstaken from the patient (e.g., autograft), from another donor source(e.g., allograft or xenograft), and orthobiologics.

After the bone growth substance is applied to the fixation assembly, theaccess device is removed. Absent the retracting force provided by theaccess device, the patient's tissue generally collapses onto the bonegrowth substance. The tissue will thereby maintain the position of thebone growth substance adjacent to the fixation assembly. The presence ofthe bone growth substance can cause bone to bridge across from thevertebra(e) to one or more components of the fixation assembly.

In a fourth method, substantially the same steps as set forth above inconnection with the second method would be performed. That is, an ALIFprocedure is performed anteriorly, and a decompression procedure and afixation procedure are performed through the access device which may beplaced generally posteriorly, e.g., postero-laterally, tranforaminally,or posteriorly. In addition, bone growth substance is placed in andaround a fixation assembly through the access device, as discussed abovein connection with the third method. The bone growth substanceencourages bone to bridge across from the vertebrae to the fixationassembly.

In a fifth method, an ALIF procedure is performed, as discussed above inconnection with the second method. After one or more fusion devices isplaced in the interbody space, access is provided by way of the accessdevice, as discussed above, from any suitable anatomical approach, e.g.,a generally posterior approach. Preferably, a postero-lateral approachis provided. After access has been provided, a bone growth substance,such as those discussed above in connection with the third method, isdelivered through the access device. The bone growth substance is placedadjacent an interbody space, e.g., the space between the L4 and the L5vertebrae and/or between the L5 and the S1 vertebrae. The bone growthsubstance encourages fusion of the adjacent vertebrae, e.g., L4 to L5and/or L5 to S1, by stimulating or enhancing the growth of bone betweenadjacent vertebrae, as discussed above.

In a sixth method, substantially the same steps described in connectionwith the first method are performed, except that the fixation procedureis optional. In one variation of the sixth method, the fixationprocedure is not performed. However, after the access device isinserted, a bone growth substance is placed in and around one or moreinterbody spaces through the access device. Where the sixth methodinvolves a two level procedure, the bone growth substance can be placedadjacent the interbody space between the L4 and the L5 vertebra and/orbetween the L5 and the S1 vertebra. Thus, bone growth may occur in theinterbody space and adjacent the interbody space between the vertebrae.

The foregoing discussion illustrates that an ALIF procedure can becombined with a variety of procedures that can be performed through anaccess device disclosed herein. In addition, though not expressly setforth herein, any combination of the procedures discussed above, and anyother suitable known procedure, may also be combined and performedthrough the access devices described herein, as should be understood byone skilled in the art.

B. Spine Procedures Providing Minimally Invasive Lumbar Interbody Fusion

Another category of procedures that may be performed with the accessdevices and systems described above involves a minimally invasive lumbarinterbody fusion (referred to herein as a “MILIF”). MILIF procedures areparticularly advantageous because they permit the surgeon to perform awide variety of therapeutic procedures without requiring fusion by wayof an anterior approach, as is required in an ALIF. This provides afirst advantage of allowing the surgeon to perform all procedures fromthe same side of the patient and also possibly from the same approach.Also, the access devices and systems disclosed herein provide thefurther advantage of enabling two level procedures, and many otherrelated procedures, to be performed by way of a single percutaneousaccess. These and other advantages are explained more fully below.

In a first MILIF method, a two level postero-lateral fixation of thespine involving three adjacent vertebrae, such as the L4, L5, and S1vertebrae, is provided. Analogous one level procedures and two levelprocedures involving any other three vertebrae also may be provided. Inaddition, the access devices and systems described herein could be usedor modified to accommodate other multi-level procedures, such as a threelevel procedure. The surgeon inserts an access device such as describedherein to a surgical location near the spine. As discussed above, theaccess devices are capable of a wide variety of anatomical approaches.In this procedure, a postero-lateral approach is preferred. Once theaccess device is inserted to a location adjacent the spine, as discussedabove, it may be configured, e.g., expanded, as discussed above, to aconfiguration wherein sufficient access is provided to the surgicallocation.

Any suitable fusion process may then be performed. For example, animplant may be advanced through the access device into the interbodyspace in order to maintain disc height and allow bone growth therein,e.g., as in a fusion procedure. In order to ease insertion of theimplant, it may be beneficial to prepare the interbody space. Interbodyspace preparation may involve removal of tissue or adjusting the heightof the interbody space through the access device, such as in adistraction procedure. Once the interbody space is prepared, a suitableimplant may be advanced through the access device into the interbodyspace, taking care to protect surrounding tissues. Various embodimentsof implants and techniques and tools for their insertion are describedin U.S. application Ser. No. 10/280,489, incorporated by referenceherein. In general, the implant preferably is an allograft strut that isconfigured to maintain disc height and allow bone growth in theinterbody space.

In addition to providing a suitable fusion, the first method providesfixation of the vertebrae. The fixation procedure may take any suitableform, e.g., any of the fixation procedures similar to those disclosedabove. In particular, when the access device is in the expanded orenlarged configuration, fixation of the three adjacent vertebrae may beperformed. One fixation procedure that could be used is discussed abovein connection with FIG. 36 wherein the fasteners 600 a, 600 b, and 600 care advanced through the access device 20 to three adjacent vertebraeand are attached to the vertebrae. The three fasteners 600 a, 600 b, and600 c are interconnected by way of the elongated member 650. Asdiscussed above, a second fixation assembly may be applied to thepatient on the opposite side of the spine, e.g., about the same locationon the opposite side of the medial line of the spine.

In a second MILIF method, substantially the same procedures set forthabove in connection with the first MILIF method are performed. Inaddition, a suitable decompression procedure may be performed, asneeded. As discussed above, decompression involves removal of unwantedbone by way of a suitable decompression technique that may be performedthrough the access device. In one embodiment, decompression is performedthrough the access device after the access device has been expanded. Asdiscussed above, suitable decompression techniques include alaminectomy, a facetectomy, or any other similar procedure.Decompression for the L4, the L5, and/or the S1 vertebrae may be neededand can be performed through the access devices described herein withoutrequiring the access device to be moved from one position to another.

In a third MILIF method, substantially the same procedures set forthabove in connection with the first MILIF method are performed. Inaddition, a further fusion procedure, e.g., a fusion procedure externalto the interbody space, is provided. The external fusion procedure isperformed adjacent to the interbody space wherein bone growth may bepromoted in the proximity of the fixation assembly, e.g., above thepostero-lateral boney elements of the spine, such as the facet jointsand the transverse processes. In one embodiment, when the fixationassembly comprising the fasteners 600 a, 600 b, 600 c and/or theelongate element 650 has been applied to three adjacent vertebrae, asubstance is applied through the access device to one or more componentsof the fixation assembly to maintain or enhance the formation and/orgrowth of bone in the proximity of the fixation assembly. For example, abone growth substance may be placed adjacent any of the fasteners 600 a,600 b, 600 c and/or the elongate member 650. Bone growth substance maytake any suitable form, e.g., small bone chips taken from the patient(e.g., autograft), from another donor source (e.g., allograft orxenograft), and orthobiologics.

After the bone growth substance is applied to the fixation assembly, theaccess device is removed. Absent the retracting force provided by theaccess device, the patient's tissue generally collapses onto the bonegrowth substance. The tissue will thereby maintain the position of thebone growth substance adjacent to the fixation assembly. The presence ofthe bone growth substance advantageously causes bone to grow between thevertebrae and the fixation assembly to form a bridge therebetween.

A fourth MILIF method involves substantially the same proceduresperformed in connection with the third MILIF method. In particular, oneor more implants are positioned in the interbody spaces through anaccess device, a fixation procedure is performed through the accessdevice, and a further fusion procedure is performed wherein bone growthsubstance is positioned adjacent the interbody space through the accessdevice. In addition, a decompression procedure is performed through theaccess device that may include a facetectomy and/or a laminectomy.

A fifth MILIF method involves substantially the same proceduresperformed in connection with the first MILIF method, except that thefixation is optional. In one embodiment, the fixation is not performed.In addition, a further fusion procedure is performed through the accessdevice wherein bone growth substance is positioned adjacent theinterbody space, as discussed above.

A sixth MILIF method is substantially the same as the fifth MILIFmethod, except that a further fusion procedure is performed through theaccess device. In particular, an implant is positioned in the interbodyspace through an access device, a decompression procedure is performedthrough the access device, and a further fusion procedure is performedwhereby bone growth substance is placed adjacent the interbody spacethrough the access device. As discussed above, the decompressionprocedure may include a facetectomy, a laminectomy, and any othersuitable procedure. As with any of the methods described herein, theprocedures that make up the sixth MILIF method may be performed in anysuitable order. Preferably the decompression procedure is performedbefore the external fusion procedure.

The foregoing discussion illustrates that a MILIF procedure can includea variety of procedures that can be performed through an access devicedescribed herein. In addition, though not expressly set forth herein,any combination of the procedures discussed above, and any othersuitable known procedures, may also be combined, as should be understoodby one skilled in the art.

C. Other Multi-level Procedures

While the foregoing procedures have involved interbody fusion, theaccess devices and systems described herein can be employed in a varietyof single level and multi-level procedures (e.g., more than two levels)that do not involve an interbody fusion. For example, a discectomy canbe performed through the access devices described herein withoutimplanting an interbody fusion device thereafter, e.g., to remove aherniation. In another embodiment, a discectomy can be performed in morethan one interbody space without inserting an interbody fusion deviceinto each interbody space, e.g., to remove multiple herniations. Inanother embodiment, a single or multi-level decompression procedure canbe performed to remove unwanted bone growth.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications,alterations, and combinations can be made by those skilled in the artwithout departing from the scope and spirit of the invention. Someadditional features and embodiments are described below.

III. Additional Features and Embodiments of Systems and Methods forPerforming Surgical Procedures

FIGS. 67-75 illustrate various embodiments of another access devicedesignated by reference number 5000. The term “access device” is used inits ordinary sense to mean a device that can provide access and is abroad term and it includes structures having an elongated dimension anddefining a passage, e.g., a cannula or a conduit. With reference toFIGS. 67 and 68, the access device 5000 is configured to be insertedthrough the skin of the patient to provide access during a surgicalprocedure to a surgical location within a patient, e.g., a spinallocation. The term “surgical location” is used in its ordinary sense(i.e. a location where a surgical procedure is performed) and is a broadterm and it includes locations subject to or affected by a surgery. Theterm “spinal location” is used in its ordinary sense (i.e. a location ator near a spine) and is a broad term and it includes locations adjacentto or associated with a spine that may be sites for surgical spinalprocedures. The access device 5000 also can retract tissue to providegreater access to the surgical location.

The access device 5000 has an elongate body 5002 that has a proximal end5004 and a distal end 5006. With reference to FIGS. 67 and 68, theelongate body 5002 has a length 5008 between the proximal end 5004 andthe distal end 5006. The length 5008 is selected such that when theaccess device 5000 is applied to a patient during a surgical procedure,the distal end 5006 can be positioned inside the patient adjacent thespinal location. When so applied, the proximal end 5004 is preferablyoutside the patient at a suitable height, as discussed more fully below.

In one embodiment, the elongate body 5002 comprises a proximal portion5010 and a distal portion 5012. The proximal portion 5010 has an oblongor generally oval shaped cross section in one embodiment. The term“oblong” is used in its ordinary sense (i.e., having an elongated form)and is a broad term and it includes a structure having a dimension,especially one of two perpendicular dimensions, such as, for example,width or length, that is greater than another and includes shapes suchas rectangles, ovals, ellipses, triangles, diamonds, trapezoids,parabolas, and other elongated shapes having straight or curved sides.The term “oval” is used in its ordinary sense (i.e., egg like orelliptical) and is a broad term and includes oblong shapes having curvedportions.

The distal portion 5012 is expandable in one embodiment. At least onepassage 5014 extends through the elongate body 5002 between the proximalend 5004 and the distal end 5006, e.g., through the proximal and distalportions 5010, 5012. The passage 5014 is defined by a smooth metal innersurface 5016 that extends substantially entirely around the perimeter ofthe passage 5014 between the proximal and distal ends 5004, 5006 in oneembodiment. The inner surfaces 5016 can take other forms, e.g.,employing other materials, different but generally constant smoothness,and/or varying degrees of smoothness.

In one embodiment, the elongate body 5002 is expandable from a firstconfiguration, shown in FIG. 72, to a second configuration, shown inFIG. 71. In one embodiment, the elongate body 5002 is movable from thefirst configuration to the second configuration when inserted within thepatient, as discussed above. In the first configuration, the accessdevice 5000 is configured, e.g., sized, for insertion into the patient.As discussed more fully below, in one embodiment, the passage 5014 has arelatively small transverse cross-sectional area at the distal end 5006of the first configuration of the access device 5000. For example, thepassage 5014 can have a cross-sectional area about equal to thecross-sectional area of the proximal end 5004, or less.

In the second configuration, the cross-sectional area of the passage5014 at the distal end 5006 is greater than the cross-sectional area ofthe passage 5014 at the proximal end 5004 in one embodiment. The secondconfiguration is particularly well suited for performing surgicalprocedures in the vicinity of a spinal location. Other configurationsand arrangements of the access device 5000 are discussed herein below.

As shown in FIGS. 67 and 68, in one embodiment, the proximal portion5010 and the distal portion 5012 are discrete, i.e., separate members.In other embodiments, the proximal and distal portions 5010, 5012 are aunitary member. In the illustrated embodiment, the proximal portion 5010comprises an oblong, generally oval shaped cross section over theelongated portion. It will be apparent to those of skill in the art thatthe cross section can be of any suitable oblong shape. The proximalportion 5010 can be any desired size. The proximal portion 5010 can havea cross-sectional area that varies from one end of the proximal portion5010 to another end. For example, the cross-sectional area of theproximal portion 5010 can increase or decrease along the length of theproximal portion 5010. Preferably, the proximal portion 5010 is sized toprovide sufficient space for inserting multiple surgical instrumentsthrough the elongate body 5002 to the surgical location. In oneembodiment, the cross-sectional area of the proximal portion 5010 canhave a generally elliptical shape. In some embodiments, the generallyelliptical shape can include generally straight side portions.

As shown in FIG. 67, the generally oval shaped cross section of theproximal portion 5010 in one embodiment has a first dimension 5026 ofabout 24 mm and a second dimension 5028 of about 35 mm. The first andsecond dimensions 5026, 5028 could range from at least about 10 mm up toabout 70 mm or more. The proximal portion 5010 in one embodiment has athird dimension 5030 of about 50 mm, but the third dimension 5030 couldrange from about 10 mm up to about 180 mm or more. In one embodiment,the proximal portion 5010 extends distally at least partially into thedistal portion 5012 of the device 5000, as shown in FIG. 70. In FIG. 67,the proximal portion 5010 extends a distance 5032 of about 10 mm intothe distal portion 5012. The proximal portion 5010 can extend a distance5032 of between about 5 mm and about 20 mm into the distal portion 5012in some embodiments. The exposed portion of the proximal portion 5010(e.g., the portion thereof that extends proximally of the distal portion5012) can be of any suitable height. Additionally, the distance 5032that the proximal portion 5010 extends into the distal portion 5012 canbe increased or decreased, as desired.

As shown in FIGS. 67 and 68, the proximal portion 5010 is coupled withthe distal portion 5012, e.g., with one or more couplers 5050. Theproximal and distal portions 5010, 5012 are coupled on a first lateralside 5062 and on a second lateral side 5064 with the couplers 5050 inone embodiment. When applied to a patient in a posterolateral procedure,either of the first or second lateral sides 5062, 5064 can be a medialside of the access device 5000, i.e., can be the side nearest to thepatient's spine. The couplers 5050 can be any suitable coupling devices,such as, for example, rivet attachments. In one embodiment, the couplers5050 are located on a central transverse plane of the access device5000.

The couplers 5050 preferably allow for at least one of rotation andpivotal movement of the proximal portion 5010 relative the distalportion 5012. A portion of the range of rotation and pivotal movement ofthe proximal portion 5010 relative the distal portion 5012 can be seenby comparing the position of the proximal portion 5010 in FIG. 67 to theposition thereof in FIG. 69. In FIG. 69, the proximal portion 5010 isseen at an angle α of about 20 degrees with respect to a transverseplane extending vertically through the couplers. One skilled in the artwill appreciate that rotating or pivoting the proximal portion 5010 tothe angle α permits enhanced visualization of and access to a differentportion of the spinal location accessible through the access device 5000than would be visualized and accessible at a different angle. Dependingon the size of the distal portion 5012, the angle α can be greater than,or less than, 20 degrees. Preferably, the angle α is between about 10and about 40 degrees.

The pivotable proximal portion 5010 allows for better access to thesurgical location and increased control of surgical instruments.Additionally, the generally oval shape of the proximal portion 5010 hasincreased the cross-sectional area available for a variety ofprocedures, some of which may require or benefit from more proximal endexposure. Embodiments having a generally oval shape can also be employedadvantageously in procedures such as the lateral or postero-lateralplacement of artificial disks, as well as other developing procedures.

As discussed above, the distal portion 5012 is expandable in oneembodiment. As shown in FIG. 70, the degree of expansion of the distalportion 5012 is determined by an amount of overlap between a first skirtmember 5034 and a second skirt member 5036 in one embodiment. Inparticular, the first skirt member 5034 has a first overlapping portion5090 on the first lateral side 5062 and the second skirt member 5036 hasa second overlapping portion 5092 on the first lateral side 5062. Thefirst skirt member 5034 has a third overlapping portion 5094 on thesecond lateral side 5064 and the second skirt member 5036 has a fourthoverlapping portion 5096 on the second lateral side 5064. The first andsecond overlapping portions 5090, 5092 overlap to define a first overlaparea 5098. The third and fourth overlapping portions 5094, 5096 overlapto define a second overlap area 5100. The extents of the first andsecond overlap areas 5098, 5100 preferably are reduced when the distalportion 5012 is in the second configuration. The extents of the firstand second overlap areas 5098, 5100 preferably are increased when thedistal portion 5012 is in the first configuration.

The distal portion 5012 preferably is manufactured from a rigidmaterial, such as stainless steel. The distal portion 5012 of the accessdevice 5000 can be manufactured from a sheet of stainless steel having athickness of between about 0.003-0.010 inches (0.076-0.254 mm). In someembodiments, the thickness is about 0.007 inches (0.178 mm). Nitinol,plastics, and other suitable materials can also be used.

In some embodiments, the distal portion 5012 can be manufactured so thatit normally assumes an expanded configuration. Additionally, the distalportion 5012 can assume an intermediate configuration and correspondingcross-sectional area, which has greater dimensions than the firstconfiguration, and smaller dimensions than the second configuration.Alternatively, an expander apparatus, similar to those previouslydiscussed herein, can be used to expand the distal portion 5012 asuitable amount.

The skirt members 5034, 5036 preferably are slidably coupled together.In one embodiment, the first and second skirt members 5034, 5036 areslidably coupled with each other with at least one guide member disposedin at least one slot defined in each of the skirt members 5034, 5036. Inparticular, a first slot 5102 is formed in the first overlapping portion5090 of the first skirt member 5034 and a second slot 5104 is formed inthe second overlapping portion 5092 of the second skirt member 5036 onthe first lateral side 5062 of the access device 5000. A guide member5106 extends through the first and second slots 5102, 5104 and istranslatable therein. Similarly, a third slot 5108 is formed in thethird overlapping portion 5094 of the first skirt member 5034 and afourth slot 5110 is formed in the fourth overlapping portion 5096 of thesecond skirt member 5036 on the second lateral side 5064 of the accessdevice 5000. A guide member 5112 extends through the third and fourthslots 5108, 5110 and is translatable therein.

Any suitable mechanism for slidably coupling the skirt members 5034,5036 can be used. In the illustrated embodiment, two floating rivets areused as guide members 5106, 5112. In another embodiment, one or more ofthe slots 5102, 5104, 5108, 5110 can include a locking or ratchetingmechanism (not shown). Locking mechanism is used in its ordinary sense(i.e. a mechanism to maintain relative positions of members) and is abroad term and it includes structures having detent arrangements,notches, and grooves. Some additional examples of locking mechanisms aredisclosed in U.S. patent application Ser. No. 10/361,887, filed Feb. 10,2003, entitled “Structure for Receiving Surgical Instruments,” publishedas application publication No. US2003/0153927 on Aug. 14, 2003, which ishereby incorporated by reference herein in its entirety.

With reference to FIGS. 67-72, as discussed above, the skirt members5034, 5036 preferably pivot about couplers 5050 joining the proximalportion 5010 with the distal portion 5012. The distal portion 5012preferably pivots on an axis perpendicular to the longitudinal axis ofthe access device 5000. This arrangement is particularly useful forproviding surgical access to anatomical features generally located andoriented along the Cephalad-Caudal direction.

As discussed above, the access device 5000 can be expanded from thefirst configuration to the second configuration by way of the movementof the first skirt member 5034 relative to the second skirt member 5036.In the illustrated embodiment, the distal portion 5012 is generally ovalshaped both in the first configuration, when the device 5000 isgenerally contracted, and in the second configuration, when the device5000 is generally expanded. However, the distal portion 5012 may beconfigured to transition from a generally circular cross-section distalend (or other convenient shape) in the first configuration to agenerally oval cross-section distal end in the second configuration.

As best seen in FIG. 72, the distal portion 5012 preferably has a firstdimension 5052 in the first configuration of approximately 24 mm and asecond dimension 5054 of approximately 35 mm. As best seen in FIG. 71,the distal portion 5012 preferably has a first dimension 5056 ofapproximately 45 mm and a second dimension 5058 of approximately 70 mmin the second configuration. Accordingly, in one embodiment in theexpanded configuration the distal portion 5012 opens distally toapproximately 45 mm by 70 mm. The distal portion 5012 can be arranged toopen more or less, as needed or desired. For example, the distal portion5012 can take on an oval shape wherein the second dimension 5058 islonger than 70 mm, e.g., about 85 mm or more. Alternatively, the distalportion 5012 can have a shape wherein the second dimension 5058 isshorter than 70 mm, e.g., about 45 mm or less. Similarly, in someembodiments the first dimension 5052 can be longer or shorter than 45mm, e.g., about 35 mm or about 55 mm. As shown in FIG. 67, the distalportion 5012 has a height 5060 that is approximately 45 mm. However, oneskilled in the art should recognize that the height 5060 of the distalportion 5012 can be any suitable height. The height 5060 preferably iswithin the range of about 20 mm to about 150 mm. Access devices havingrelatively shorter skirt heights 5060 may be advantageous for use withpatients having relatively less muscle tissue near the surgical locationand generally require smaller incisions. Access devices havingrelatively longer skirt height 5060 may be advantageous for use withpatients having relatively more muscle tissue near the surgicallocation, and may provide greater access.

The distal portion 5012 preferably is sufficiently rigid that it iscapable of displacing surrounding tissue as the distal portion 5012expands. Depending upon the resistance exerted by the surroundingtissue, the distal portion 5012 is sufficiently rigid to provide someresistance against the tissue to remain in the second, expandedconfiguration. Moreover, the second configuration is at least partiallysupported by the body tissue of the patient. The displaced tissue tendsto provide pressure distally on the distal portion 5012 to at leastpartially support the access device 5000 in the second configuration.The rigidity of the distal portion 5012 and the greater expansion at thedistal end 5006 creates a stable configuration that is at leasttemporarily stationary in the patient, which at least temporarily freesthe physician from the need to actively support the elongate body 5002.

Another advantageous aspect of the access device 5000 is illustratedwith reference to FIGS. 71 and 72. In particular, the elongate body 5002has a first location 5068 and a second location 5070. The first location5068 is distal of the second location 5070. The elongate body 5002 iscapable of having a configuration when inserted within the patientwherein the cross-sectional area of the passage 5014 at the firstlocation 5068 is greater than the cross-sectional area of the passage5014 at the second location 5070. The passage 5014 is capable of havingan oblong shaped cross section between the second location 5070 and theproximal end 5004.

In some embodiments the passage 5014 preferably is capable of having agenerally elliptical cross section between the second location 5070 andthe proximal end 5004. Additionally, the passage 5014 preferably iscapable of having a non-circular cross section between the secondlocation 5070 and the proximal end 5004. Additionally, in someembodiments, the cross section of the passage 5014 can be symmetricalabout a first axis 5072 and a second axis 5074, the first axis 5072being generally normal to the second axis 5074.

As shown in FIG. 71, the configuration of the elongate body 5002 betweenthe first location 5068 and the second location 5070 is generallyconical, when the elongate body 5002 is expanded within the patient. Theterm “conical” is used in its ordinary sense (i.e. a surface formed byline segments joining every point of the boundary of a closed base to acommon vertex) and is a broad term and it includes structures having agenerally oblong, or oval, cross section, as well as structures having asurface that extends only partially toward a vertex. In someembodiments, the first location 5068 can be near a distal end 5006 ofthe elongate body 5002, and the second location 5070 can be near aproximal end 5004 of the elongate body 5002.

In the illustrated embodiment, the elongate body 5002 has an oblongshaped cross section near its proximal end 5004 at least when theelongate body 5002 is in the second configuration. In some embodiments,the elongate body 5002 has an oblong shaped cross section alongsubstantially the entire length between the proximal end 5004 and thesecond location 5070.

Additionally, in some embodiments the passage 5014 can have a generallyoval shaped cross section between the second location 5070 and theproximal end 5004. The elongate body preferably has a generally ovalshaped cross section at its proximal end 5004 at least when the elongatebody 5002 is in the second configuration. The elongate body 5002 canhave a generally oval shaped cross section along substantially theentire length between the proximal end 5004 and the second location5070. The passage 5014 can also have a cross section between the secondlocation 5070 and the proximal end 5004 where the cross section isdefined by first and second generally parallel opposing side portions5076, 5078 and first and second generally arcuate opposing side portions5080, 5082.

In some embodiments, it is useful to provide a structure to maintain theaccess device 5000 in an un-expanded state until expansion of the deviceis desired. As shown in FIG. 73, in one embodiment an outer sleeve 5084,e.g., a plastic sleeve, is provided which surrounds the access device5000 and maintains the distal portion 5012 in the first configuration.The outer sleeve 5084 can be produced to function as previouslydescribed herein with reference to other embodiments. For example, theouter sleeve 5084 can have a braided polyester suture 5086 embeddedwithin it, aligned substantially along the longitudinal axis thereof,such that when the suture 5086 is withdrawn, the sleeve 5084 is torn,which allows the access device 5000 to expand, either resiliently ormechanically, from the first configuration to the second configuration.

In a method for accessing a surgical location within a patient an accessdevice, such as the access device 5000, is provided. As stated above,the elongate body 5002 is capable of having a first configuration sizedfor insertion into the patient. The elongate body 5002 is capable ofhaving a second configuration when expanded within the patient. In thesecond configuration, the cross-sectional area of the passage 5014 at afirst location 5068 is greater than the cross-sectional area of thepassage 5014 at a second location 5070. The first location 5068 isdistal to the second location 5070. The passage 5014 is capable ofhaving an oblong shaped cross section between the second location 5070and the proximal end 5004. The method comprises inserting the accessdevice 5000, in the first configuration, into the patient to thesurgical location and expanding the device to the second configuration.

The access device 5000 is inserted to a spinal location in some methods.As shown in FIG. 73, an oblong shaped dilator 5088 preferably isinserted into the patient prior to insertion of the access device 5000.In some applications, the access device 5000 may be inserted laterallyto the spinal location. In other applications, the device 5000 isinserted posterolaterally to the spinal location. In some applications,the device 5000 is inserted anteriorly to the spinal location. Thedevice 5000 preferably can be expanded in a cephalad-caudal direction ata spinal location.

With reference to FIG. 73, an early stage in one method involvesdetermining an access point in the skin of the patient to insert theaccess device 5000. An incision is made at the determined location. Insome cases, the incision is approximately 1″ to 2″ long. A guide wire(not shown) is introduced under fluoroscopic guidance through theincision and past the skin, fascia, and muscle to the approximatesurgical site. A series of oblong, or generally oval shaped, dilators isused to sequentially expand the incision to the desired widths, about 24mm by 35 mm for the illustrated embodiment, without damaging thestructure of surrounding tissue and muscles. In one technique, a firstoblong dilator is placed over the guide wire, which expands the opening.The guide wire is then subsequently removed. A second oblong dilatorthat is slightly larger than the first dilator is placed over the firstdilator, which expands the opening further. Once the second dilator isin place, the first dilator is subsequently removed. This process of (1)introducing a next-larger-sized dilator coaxially over the previousdilator and (2) subsequently removing the previous dilator when thenext-larger-sized dilator is in place continues until an opening of thedesired size is created in the skin, muscle, and subcutaneous tissue.For the illustrated embodiment, these dimensions are about 24 mm byabout 35 mm. (Other dimensions for the openings that are useful withsome embodiments in connection with spinal surgery range from about 20mm to about 50 mm, and still other dimensions are contemplated.) Inother techniques, a series of dilators having circular (or other shaped)cross-sections are used to partially dilate the opening. Then, a finaldilator having a circular inner diameter and an oblong or generally ovalshaped outer perimeter can be used to further dilate the opening.

As illustrated in FIG. 73, following placement of the largest oblong, orgenerally oval shaped dilator 5088, the access device 5000, in the firstconfiguration, is introduced and positioned in a surroundingrelationship over the dilator 5088. The dilator 5088 is subsequentlyremoved from the patient, and the access device 5000 is allowed toremain in position.

Once the access device 5000 is positioned in the patient, it can beenlarged to provide a passage 5014 for the insertion of various surgicalinstrumentation and an enlarged space for performing the proceduresdescribed herein. As described above, the elongate body 5002 canaccommodate the enlargement in several ways. In the illustratedembodiment, the distal portion 5012 of the device 5000 can be enlarged,and the proximal portion 5010 can maintain an oblong shape. The relativelengths of the proximal portion 5010 and the distal portion 5012 can beadjusted to vary the overall expansion of the access device 5000.Alternatively, in some embodiments expansion can extend along the entirelength of the elongate body 5002.

In the illustrated embodiment, the access device 5000 can be expanded byremoving the suture 5086 and tearing the sleeve 5084 surrounding theaccess device 5000, and subsequently expanding the distal portion 5012mechanically, or allowing the distal portion 5012 to resiliently expandtowards the expanded configuration, to create an enlarged surgicalspace. In some embodiments, the enlarged surgical space extends from theL4 to the S1 vertebrae.

The access device 5000 can be enlarged at its distal portion 5012 usingan expander apparatus to create a surgical access space. An expanderapparatus useful for enlarging the elongate body 5002 has a reducedprofile configuration and an enlarged configuration. Additionally, theexpander apparatus can have an oblong, or generally oval shape. Theexpander apparatus is inserted into the elongate body 5002 in thereduced profile configuration, and subsequently expanded to the enlargedconfiguration. The expansion of the expander apparatus also causes theelongate body 5002 to be expanded to the enlarged configuration. In someembodiments, the expander apparatus can increase the cross-sectionalarea of the elongate body 5002 along substantially its entire length. Inother embodiments, the expander apparatus expands only a distal portion5012 of the elongate body 5002, allowing a proximal portion 5010 tomaintain a constant oblong, or generally oval shape. Other expanderapparatus are disclosed in U.S. patent application Ser. No. 10/665,754,entitled “Surgical Tool for Use in Expanding a Cannula”, filed on Sep.19, 2003.

In addition to expanding the elongate member 5002, the expanderapparatus can also be used to position the distal portion 5012 of theelongate member 5002 at the desired location for the surgical procedurein a manner similar to that described previously with reference toanother embodiment.

Once the distal portion 5012 has expanded, the rigidity and resilientcharacteristics of the distal portion 5012 allow the elongate body 5002to resist closing to the first configuration and to at least temporarilyresist being expelled from the incision. These characteristics create astable configuration for the elongate body 5002 to remain in position inthe body, supported by the surrounding tissue.

The access device 5000, like the other access devices described herein,has a wide variety of applications wherein the passage 5014 providesaccess to one or more surgical instruments for performing a surgicalprocedure. In one application, the passage 5014 provides access toperform a two level posterolateral fixation of the spine involving theL4, L5 and S1 vertebrae. The access devices 5000 can be used to delivera wide variety of fixation elements, including rigid, semi-rigid, ordynamic fixation elements. The access devices are not limited to theposterolateral approach nor to the L4, L5 and S1 vertebrae. The accessdevices may be applied in other anatomical approaches and with othervertebrae within the cervical, thoracic and lumbar spine. The accessdevices can be applied in procedures involving one or more vertebrallevels and in anterior and lateral procedures. Further procedures inwhich the access devices described herein can be applied includeprocedures involving orthobiologics, bone morphogenetic proteins, andblood concentrators. The access devices can also be used with proceduresinvolving prosthetics, such as disc nucleus replacement, facet jointreplacement, or total disc replacement. The access devices can also beapplied in procedures involving vertebroplasty, where a crushed vertebrais brought back to its normal height.

The access devices described herein also can be used in connection withinterbody fusion, and fusion of the facets and transverse processes.Some of the fusion procedures that can be performed via the accessdevices described herein employ allograft struts, bone filling material(e.g., autograft, allograft or synthetic bone filling material), andcages and/or spacers. The cages and the spacers can be made of metal, apolymeric material, a composite material, or any other suitablematerial. The struts, cages, and spacers are used in the interbody spacewhile the bone filling material can be used both interbody andposterolaterally. Any of the foregoing or other fusion procedures can beused in combination with the orthobiologics and can be performed via theaccess devices described herein.

Some examples of uses of the access devices described in otherprocedures and processes, as well as further modifications andassemblies, are disclosed in U.S. patent application Ser. No.10/845,389, filed May 13, 2004, entitled “Access Device For MinimallyInvasive Surgery,” and in U.S. patent application Ser. No. 10/658,736,filed Sep. 9, 2003 which are hereby incorporated by reference herein intheir entireties.

FIGS. 74-79 illustrate embodiments having lighting elements. FIGS. 74-76illustrate one embodiment of a lighting element 5120 coupled with asupport arm 5122 compatible with an access device 5124 having a proximalportion with a generally circular cross section. In other embodiments,support arms can be configured to be coupled with access devices havingproximal portions with generally oblong or oval cross sections.

The support arm 5122 preferably is coupled with the access device 5124to provide support for the access device 5124 during a procedure. Asshown in FIGS. 74 and 75, the support arm 5122 comprises a pneumaticelement 5126 for maintaining the support arm 5122 in a desired position.Depressing a button 5128 coupled with a valve of the pneumatic element5126 releases pressure and allows the support arm 5122 and access device5124 to be moved relative the patient 5130. Releasing the button 5128 ofthe pneumatic element 5126 increases pressure and maintains the accessdevice 5124 and support arm 5122 in the desired position. The supportarm 5122, as shown, is configured for use with a mechanical arm usingsuction, or a vacuum to maintain the access device in a desiredlocation. One of skill in the art will recognize that various othersupport arms and mechanical arms can be used. For example, commerciallyavailable mechanical arms having clamping mechanisms can be used as wellas suction or pressure based arms.

As shown in FIGS. 74-76, the support arm 5122 can comprise an inner ringportion 5132 and an outer ring portion 5134 for surrounding the accessdevice 5124 at its proximal end. In the illustrated embodiment, theinner and outer ring portions 5132, 5134 are fixed relative each other.In other embodiments the inner and outer ring portions 5132, 5134 canmove relative each other. The support arm 5122 preferably comprises alighting element support portion 5136. In the illustrated embodiment,the lighting element support portion 5136 extends above upper surfacesof the inner and outer ring portions 5132, 5134. The lighting elementsupport portion 5136 can extend from the inner ring portion 5132, theouter ring portion 5134, or both. The lighting element support portion5136 can have a notch or groove 5138 for receiving and supporting thelighting element 5120. Additionally, the lighting element supportportion 5136 can have one or more prongs extending at least partiallyover the lighting element 5120 to hold it in place.

In the illustrated embodiment, the lighting element 5120 has anelongated proximal portion 5140 and a curved distal portion 5142. Theproximal portion 5140 of the lighting element 5120 preferably is coupledwith a light source (not shown). The curved distal portion of thelighting element 5120 in one embodiment extends only a short distanceinto the access device and is configured to direct light from the lightsource down into the access device 5124. In another embodiment, thelighting element 5120 can be provided such that it does not extend intothe access device. In such an embodiment, the right portions 5132 and5134 only partially surround the proximal end of the access device 5124.Providing a lighting element 5120 for use with the access device 5124preferably allows a user to see down into the access device 5124 to viewa surgical location. Accordingly, use of a lighting element 5120 can, insome cases, enable the user to perform a procedure, in whole or in part,without the use of an endoscope. In one embodiment, the lighting element5120 enables a surgeon to perform the procedure with the use ofmicroscopes or loupes.

FIGS. 74-79 illustrate other embodiments of lighting elements. As shownin FIG. 77, a lighting element 5160 comprises a support member 5162, anaccess device insert 5164, and fiber optic elements 5166. The supportmember 5162 has a proximal end 5168, a central portion 5170, and adistal end 5172. The proximal end 5168 preferably has a coupling portion5174 for coupling the support member 5162 to a support arm or othersupport system (not shown). The central portion 5170 preferably iscoupled with the fiber optic elements 5166 to provide support there to.The distal end 5172 preferably is coupled with the access device insert5164.

In the illustrated embodiment, the access device insert 5164 isconfigured to be inserted in an access device having a proximal portionwith a generally circular cross section. The access device insert 5164is coupled with the fiber optic elements 5166. The fiber optic elements5166 extend down into the access device insert 5164 so that the ends ofthe fiber optic elements 5166 can direct light down inside an accessdevice along side portions there of.

FIGS. 78 and 79 illustrate other embodiments of lighting elementssimilar to the embodiment described with reference to FIG. 77.Components of the lighting elements shown in FIGS. 108 and 109 that weredescribed with reference to FIG. 77 are given the same referencenumerals that were used in FIG. 77, except that an “a” is added in FIG.78 and a “b” is added in FIG. 79. As shown in FIGS. 78 and 79, accessdevice inserts 5164 a, 5164 b are configured to be inserted into accessdevices having proximal portions with generally oblong, or oval, crosssections. As shown in FIG. 78, the access device insert 5164 a has agenerally oblong or oval shaped cross section. The access device insert5164 a is coupled with the fiber optic elements 5166 a along a longerside surface of the access device insert 5164 a. As shown in FIG. 79,the access device insert 5164 b has a generally oblong or oval shapedcross section. The access device insert 5164 b is coupled with the fiberoptic elements 5166 b along a shorter side surface of the access deviceinsert 5164 b. Use of an illumination element with an expandable accessdevice having an oblong shaped proximal section, in some cases, allows adoctor to perform procedures that would be difficult to perform using anendoscope. Increased visualization of the surgical location through theaccess device can simplify some procedures. For example, decompressionof the contra-lateral side can be achieved more easily in some caseswithout the use of an endoscope.

FIGS. 80 and 81 show an access assembly 6000 that can be incorporatedinto a surgical system, such as the system 10. The access assembly 6000includes an access device or retractor 6010 coupled with a mount fixture6014. The mount fixture 6014 may be coupled with a support arm, such asthose discussed above. The access device 6010 preferably is providedwith an oblong transverse cross-section near the proximal end thereof,which can be coupled with the mount fixture 6014. More preferably, theaccess device 6010 can be provided with an oval transverse cross-sectionin some embodiments. The cross section can be generally elliptical insome embodiments. The oblong shaped cross-section of the access device6010 is particularly beneficial for surgical procedures (such as twolevel pedicle screw fixation) that are performed at an elongatedsurgical field. Also coupled with the mount fixture 6014 is a guidefixture 6016. In one embodiment, the guide fixture 6016 is configured tobe coupled with a viewing element 6018, such as any of those discussedherein, or any other suitable viewing element.

The mount fixture 6014 and the guide fixture 6016 advantageously areconfigured to introduce the viewing element 6018 into the access device6010 at discrete locations. In the illustrated embodiment, the mountfixture 6014 and the guide fixture 6016 are configured to enable aviewing element to be positioned at four discrete locations that arelocated at opposite corners of the elongated mount fixture 6014. In theillustrated embodiment, a plurality of holes 6022 (e.g., two holes) isprovided at each of four corners on the top surface of the mount fixture6014. Each of the holes 6022 is configured to receive a pin that extendsfrom the lower surface of the guide fixture 6016. The engagement of thepins in the holes 6022 is such that the guide fixture 6016 is securelycoupled with the mount fixture 6014 so that the guide fixture 6016 willnot be dislodged inadvertently during a procedure. However, theengagement of the pins in the holes 6022 also is such that a user of theaccess assembly 6000 can disengage the guide fixture 6016 and theviewing element 6018 and reposition it at any of the other discretelocations during a procedure. Although the coupling of the mount fixture6014 and the guide fixture 6016 is illustrated as a two hole-two pinarrangement, other arrangements are possible and contemplated. Forexample, more or less than two holes and pins, couplers of other shapes(e.g., pins and holes of different shapes, tongues and slots, etc.), andclamp devices could be used in place of or in combination with theillustrated two hole-two pin arrangement.

FIG. 82 shows one embodiment of the access device 6010 that is similarto those hereinbefore described, except as set forth below. The accessdevice 6010 has an elongate body with a distal portion 6028 and aproximal portion 6032. Each of the distal and proximal portions 6028,6032 defines a portion of a passage that extends through the accessdevice 6010. In some embodiments, the distal portion 6028 of the accessdevice 6010 is shorter compared to the distal portion of some of theother access devices described herein. In particular, the distal portion6028 is configured such that when the access device 6010 is applied tothe patient, the distal portion 6028 is completely or substantiallycompletely beneath the skin, as discussed below. This arrangement isadvantageous in that the access device 6010 does not need to furtherdilate the incision at the skin.

Although the illustrated embodiment of the access device 6010 has twodiscrete portions that are coupled in a suitable manner, other accessdevices embodying features discussed herein can be configured withoutmultiple, discrete portions. Both the proximal and distal portionspreferably are made from a rigid, radiolucent material that is visibleunder fluoroscopy. The distal and proximal portions 6028, 6032preferably both have sufficient strength or stiffness to retract tissue,though the strength or stiffness of the proximal and distal portionsneed not be the same. Examples of materials that may be used and otherfeatures that can be incorporated into the access device 6010 arediscussed above and in the patents and applications incorporated byreference herein.

The proximal portion 6032 preferably is elongated and has a length alonga longitudinal axis 6036 that is selected based upon the anatomy (e.g.,the portion of the spine) being treated. The length of the proximalportion 6032, and other aspects of the access device 6010, also can bebased in part on the individual patient's anatomy, e.g., on the amountof tissue between the skin and the surgical location, which variesacross the patient population.

As discussed above, the configuration of at least a portion of theproximal portion 6032 is elongated in at least one direction in a planeperpendicular to the axis 6036. One advantageous arrangement of theproximal portion 6032 provides an oblong transverse cross-section.Another advantageous arrangement provides an oval transversecross-section. The configuration of the proximal portion 6032 isillustrated in FIGS. 85-86A, which show that the transversecross-section of the proximal portion 6032 is elongated along a line6040. As will be discussed in more detail below, the line 6040 extendsalong the main axis of expansion of the access device 6010.

There are several advantages to configuring the proximal portion 6032with an oblong transverse cross-section. Many bone and joint procedures,particularly spine procedures, are performed at elongated surgicalfields. For example, multi-level procedures may be much more convenientfor the surgeon and beneficial for the patient if access can be providedto at least a portion of three or more adjacent vertebrae. Whilesymmetrical access could be provided to three or more adjacentvertebrae, much non-adjacent tissue (i.e., tissue not in the immediatevicinity of the structures being treated) would be disrupted, causinggreater trauma to treat the patient than necessary. This additionaltrauma approaches that of open surgery as the length of the surgicalfield increases. In contrast, the use of an oblong transversecross-section proximal portion 6032 and access device 6010 lessens, ifnot minimizes, the amount of non-adjacent tissue that is disrupted.Oblong access from a posterior or posterolateral approach isparticularly advantageous in that it provides access to anatomy for awide variety or procedures, e.g., those that affect the pedicles.

The distal portion 6028 also extends along the longitudinal axis 6036and comprises a first overlapping portion 6050 and a second overlappingportion 6054. The first overlapping portion 6050 extends between aproximal end 6058 and a distal end 6062 of the distal portion 6028. Thesecond overlapping portion 6054 extends between the proximal end 6058and the distal end 6062 of the distal portion 6028. The overlappingportions 6050, 6054 overlap each other to create an enclosed space 6066therebetween. In one embodiment, each of the overlapping portions 6050,6054 extends along the axis 6036 when the overlapping portions arecoupled with the proximal portion 6032 and is formed from a thin, rigidmaterial (such as sheet metal) that is curled into a generally U-shapedstructure.

The first and second overlapping portions 6050, 6054 are coupled in amanner that permits expansion of the distal portion 6028 at the distalend 6062. The advantages of being able to expand the distal portion arediscussed above. The first and second overlapping portions 6050, 6054also are configured to be selectively locked or unlocked in one or morestates of expansion or contraction. Further advantages of the lockingaspect of the first and second overlapping portions 6050, 6054 arediscussed below.

In one embodiment, the distal portion 6028 has a slot and guide memberarrangement that enables expansion of the distal portion 6028.Corresponding arcuate slots 6070 a, 6070 b are formed in the firstoverlapping portion 6050 and the second overlapping portion 6054,respectively. In one embodiment, a guide member, such as a sliding rivet6074, extends through the corresponding slots 6070 a, 6070 b therebycoupling the slots. The slots 6070 a, 6070 b and the rivet 6074 enablethe distal portion 6028 to be expanded by allowing the rivet 6074 toslide along the slots as the overlapping portions 6050, 6054 move awayfrom or toward each other. In the illustrated embodiment, a second pairof slots and a corresponding guide member (e.g., a rivet) are providedon the opposite side of the access device 6010 from the slots 6070 a,6070 b and the rivet 6074. Thus, two rivets 6074 are provided incorresponding pairs of slots adjacent each edge of the overlappingsections 6050, 6054. This arrangement enables generally linear expansionof the distal portion 6028 along and parallel to a vertical planeextending along the long dimension of the proximal portion 6032 andcontaining the line 6040. Another arrangement provides one or more slotson only one side of the access device 6010, which would provide a moremulti-directional expansion (e.g., both cephalad-caudad andmedial-lateral) near the distal end 6062 of the distal portion 6028.

The distal portion 6028 is configured to be actuatable from anon-expanded configuration to an expanded configuration. Thenon-expanded configuration is said to be “low-profile” in that thetransverse cross-section of the distal portion 6028, particularly at thedistal end 6062, is relatively small. The access device 6010, like theother access devices described herein, is configured to be inserted overa dilating structure, such as a dilator or an obturator. One suitabledilator is described below in connection with FIGS. 120-122. Providing alow-profile distal end 6062 in the non-expanded configuration enables agenerally smaller dilating structure to be used, reducing the amount oftrauma to the patient during insertion. In one embodiment the distalportion 6028 has an oblong cross-section similar to that of the proximalportion 6032 when the distal portion 6028 is in a low profileconfiguration. The transverse cross-section of the distal portion 6028in the low profile configuration need not be constant from the distalend 6058 to the proximal end 6062 thereof. For example, in oneembodiment the transverse cross-section of the distal portion 6028transitions from generally circular near the distal end 6058 togenerally oblong near the proximal end 6062 (e.g., generally matchingthe transverse cross-section of the proximal portion 6062 at the distalend thereof). The distal portion 6028 may also be arranged to transitionfrom a circular cross-section configuration to a non-circularcross-section configuration.

The distal portion 6028 also is provided with a lock 6090 that enables auser to selectively lock the distal portion 6028 into one or more statesof expansion. The lock 6090 can take many forms. In one embodiment, thelock 6090 includes a slot 6094 and an L-shaped flange 6098 that can bemoved (e.g., rotated) into and out of the slot 6094.

In one embodiment, the slot 6094 extends generally perpendicularly fromthe slot 6070 a and the slot 6094 has a first side 6094 a and a secondside 6094 b. Each of the first and second sides 6094 a, 6094 b of theslot 6094 restrains relative movement of the overlapping portions 6050,6054 to selectively limit expansion or un-expansion of the distalportion 6028 when the lock 6090 is engaged.

In one embodiment, the L-shaped flange 6098 includes an elongated planarportion 6502 and a lock tab 6506. The elongated portion 6502 preferablyis relatively thin so that it may reside between the overlappingportions 6050, 6054. In one embodiment, the elongated portion 6502 isrotatably coupled (e.g., with a pin or a portion of a rivet, e.g., ahalf-rivet) with the overlapping portion 6054 near one edge thereof. Theelongate portion 6502 is thereby enabled to swing about an arc. In oneembodiment, the lock tab 6506 extends generally perpendicularly from theend of the elongated portion 6502 that is opposite the rotatably coupledend. The length of the lock tab 6506 is greater than the thickness ofthe first overlapping portion 6050. In one embodiment, the lock tab 6506extends far enough beyond the first overlapping portion 6050 into thearea defined within the access device 6010 to enable a user to engageand manipulate the lock tab 6506 in the enclosed space 6066. Where theaccess device 6010 is to be inserted over a dilating structure, the locktab 6506 preferably is configured to not interfere with the dilatingstructure. For example, the lock tab 6506 can be made short enough sothat the lock tab 6506 does not extend far enough into the enclosedspace 6066 defined inside the access device 6010 to interfere with thedilating structure. Any suitable tool may be used to articulate the lock6090, e.g., by engaging and manipulating the lock tab 6506. For example,a tool that is long enough to extend from a location proximal of theproximal end of the proximal portion 6032 to the location of the lock6090 could be used. A number of conventional tools can be configured inthis manner, including a cobb elevator, a penfield, and a nerve hook.

In one application, the access device 6010 is used to provide minimallyinvasive access to the spine for a spinal procedure, such as a one-levelor a multi-level procedure. The patient is positioned prone on aradiolucent table and draped for posterior spinal surgery. The locationof the spine anatomy to be treated is identified, e.g., via fluoroscopy.In one technique, the location of adjacent pedicles on one side of themid-line of the spine are identified. Thereafter, an incision is madethrough the skin above the adjacent pedicles. In one technique, anincision of about 30-40 mm in length is made between two adjacentpedicles where a single level procedure (one involving two adjacentvertebrae) is to be performed. In another technique where a two-levelprocedure (one involving three vertebrae) is to be performed, anincision of 40-50 mm in length is made. As discussed above, in someembodiments, the access device 6010 is configured to be applied suchthat the distal portion 6028 is completely or substantially completelysubmerged beneath the skin. In one technique, an incision of about 30 mmis made in the skin so that an access device configured to be applied inthis manner may be applied to the patient. In some embodiments of theaccess devices described herein, a proximal portion thereof isconfigured to be expandable. In some techniques for applying accessdevices with expandable proximal portions, a larger incision may be madeto accommodate all or substantially all of the expansion of the proximalportion.

Thereafter a dilating structure, such as a series of dilators or anobturator, is inserted into the incision to enlarge the incision. It maybe desirable to use round or oblong dilators. Preferably the lastdilator has an outer profile that matches the un-expanded inner profileof the access device 6010. In one technique for a single levelprocedure, a 5 mm dilator is first inserted through the skin near thecenter of the skin incision and is docked on the lateral aspect of thesuperior facet. In a two-level procedure, a 5 mm dilator is firstadvanced through the skin near the center of the incision and is dockedon the mamillo-accessory ridge of the middle pedicle. Placement of the 5mm dilator may be verified by fluoroscopy. Subsequently, progressivelylarger dilators are inserted over each other. After a larger dilator isinserted, the next-smaller dilator is normally removed. One or more ofthe dilators, a cobb device, or even one of the surgeon's fingers mayalso be used to probe and to dissect soft tissue to ease expansion ofthe access device 6010, as discussed below. Placement of the finaldilator may be verified by fluoroscopy. Other procedures employ similardilating techniques by initially approaching other anatomical featureson or near the spine.

Thereafter, the access device 6010 is advanced to the anatomy to betreated. As discussed above, a sleeve deployable by a string may beemployed to maintain the access device 6010 in the low-profileconfiguration (e.g., in the un-expanded state) until the access deviceis in place. Various embodiments of the sleeve and string are discussedherein, e.g., in connection with FIGS. 123-124. In one technique, theassembly of the access device 6010, the sleeve, and the string isinserted into the incision and positioned so that the string faces themid-line of the spine. Thereafter the string is withdrawn, releasing thesleeve from the access device 6010. In particular, in one technique, thestring is pulled from near the proximal end of the access device 6010.This action causes the sleeve to be torn along a line extendingproximally from the distal end of the sleeve. The sleeve may bepartially or completely torn from distal to proximal, releasing at leastthe distal end of the access device 6010 for expansion. After the sleeveis released from the access device 6010, the access device 6010 is freeto expand and to be expanded.

FIG. 83B shows that prior to and during expansion of the access device6010, the L-shaped flange 6098 is positioned so that the lock tab 6506is located in the arcuate slot 6070 a. The lock tab 6506 has a thicknessthat is less than the proximal to distal width of the slot 6070 a sothat the lock tab 6506 can translate along the slot 6070 a betweenpositions corresponding to the un-expanded and expanded configurationsof the access device 6010. The access device 6010 may resiliently expandwith the lock tab 6095 in the slot 6070 a. Further expansion of theaccess device 6010 may be achieved by inserting and articulating anexpander tool, such as the expander tool 200 discussed above. Theexpansion and location of the access device 6010 may be confirmed byfluoroscopy.

After the access device 6010 has been fully expanded, the lock 6090 maybe articulated to lock the access device 6010 in the expandedconfiguration. In particular, the lock tab 6098 may be positioned in theslot 6094. As discussed above, the lock tab 6098 is pivotable at the endopposite the lock tab 6506. In one procedure, the user grasps androtates the lock tab 6506 from the expansion position in the slot 6070 ato the locked position in the slot 6094. As discussed above, the lock6090 may be manipulated in any convenient manner, e.g., by any suitabletool, as discussed above. FIG. 83B shows an arrow 6510 that indicatesthe rotation of the lock tab 6098 to the locked position. When in thelocked position, the lock tab 6098 may engage one of the sides 6094 a,6094 b of the slot 6094 to prevent either inadvertent further expansionor un-expansion of the access device 6010.

In one variation, another slot analogous to the slot 6094 is provided atthe opposite end of the arcuate slot 6070 a to enable the access device6010 to be locked in the un-expanded configuration. This arrangement andvariations thereof may substitute for the sleeve and string arrangement,discussed above.

After the access device 6010 is locked in position, various proceduresmay be performed on the spine (or other joint or bone segment). Asdiscussed above, these procedures may be performed with much less traumathan that associated with open surgery. After the procedures arecomplete, the access device 6010 may be un-expanded by articulating thelock 6090 from the locked position to the unlocked position, e.g., bymoving the lock tab 6098 from the slot 6094 to the slot 6070 a, whereinit is free to translate. FIG. 83A shows an arrow 6514 that indicates therotation of the lock tab 6098 to the unlocked position.

FIG. 84 shows an arrow 6518 that indicates un-expansion of the accessdevice 6010 after the procedure is complete.

FIGS. 87-150 illustrate and describe systems, devices, components, andmethods according to some additional embodiments. Details shown ordescribed in FIGS. 87-150 are merely representative of some preferredembodiments and are not intended to limit other embodiments. Some of thesystems, devices, components, and methods shown are similar to thosedescribed above or in the documents incorporated by reference herein.Additional features and advantages of the illustrated embodiments willbe apparent to those of ordinary skill in the art in view of thedisclosure herein.

FIGS. 87-122 illustrate instrumentation, systems, devices, components,and methods according to some embodiments. FIGS. 87-122 illustrateportions of support arms, light post mounts, visualization mounts, lightposts, visualization elements, indexing collar assemblies, and dilators,according to some embodiments. These devices and components cancooperate with access devices in access systems, such as those describedand shown herein to facilitate various surgical procedures.

FIGS. 87-119 illustrate portions of a visualization assembly 7000. Thevisualization assembly 7000 preferably is configured to be coupled witha proximal portion of an access device. In the illustrated embodiment,the visualization assembly 7000 is configured to be coupled with anaccess device having a proximal portion with an oval shapedcross-sectional area. In other embodiments, the visualization assembly7000 can be configured to be coupled with a proximal portion of anaccess device having any other oblong shaped or circular shaped (assuggested in FIG. 102) cross-sectional area. In one embodiment, thevisualization assembly 7000 is configured to be coupled with an accessdevice having a proximal portion that has a generally oval shapedopening that is about 24 mm wide and about 30 mm long. In anotherembodiment, the visualization assembly can be configured to be coupledwith an access device having a proximal portion with a generally ovalshaped opening that is about 24 mm wide and about 35 mm long.

FIGS. 87 and 88 show a visualization assembly 7000 that is similar tothe other visualization assemblies described herein, except as set forthbelow. With reference to FIGS. 87 and 88, the visualization assembly7000 has a light post mount 7002. In other embodiments, other suitablevisualization element mounts can be used. The light post mount 7002 hasa distal portion 7004 and a proximal portion 7006. The distal portion7004 has a generally oval shaped mounting portion 7008. In otherembodiments, the distal portion 7004 can have any other oblong shaped orcircular shaped mounting portion 7008. A light post assembly 7010 (seeFIGS. 98-99) preferably can be supported on a mounting portion 7008 ofthe light post mount 7002. The mounting portion 7008 has an outsidesurface 7012 and an inside surface 7014. The inside surface 7014preferably defines an oblong shaped opening 7016 to provide access to apassage of an access device. In the illustrated embodiment, the insidesurface 7014 defines a generally oval shaped opening 7016.

FIGS. 89-94 show a viewing element support mount that is similar to theother viewing element support mounts described herein, except as setforth below. With reference to FIGS. 89-94, the light post mount 7002has a ledge 7018 on the inside surface 7014 of the light post mount7002. The ledge 7018 preferably is configured so that the light postmount 7002 can rest on a top surface, a top edge, or an end of aproximal portion of an access device. The inside surface 7014 of thelight post mount 7002, below the ledge 7018, can extend over a proximalportion of an access device. The mounting portion 7008 preferably hasopenings 7020, such as, for example, holes or slots, defined in the wallof the mounting portion 7008 for supporting the light post assembly 7010or other visualization tool. As shown in the illustrated embodiment, themounting portion 7008 preferably is configured to receive the light postassembly 7010 at a plurality of locations or positions.

The light post mount 7002 has a support arm 7022 extending proximallyfrom the mounting portion 7008. With reference to FIGS. 87 and 88, thesupport arm 7022 preferably is coupled with an arm extension assembly7024 via an arm locking screw 7026. With reference to FIG. 89, the lightpost mount 7002 has a spline ring 7028 at a proximal portion 7006 of thesupport arm 7022. The spline ring 7028 preferably is configured forcoupling the light post mount 7002 with the arm extension assembly 7024via the arm locking screw 7026.

With reference to FIGS. 95-97, the spline ring 7028 has a spline portion7030 and an anchor portion 7032. The spline portion 7030 preferablycomprises a plurality of notches 7034 formed in a first surface 7036 ofthe spline portion 7030 to interface with the arm extension assembly7024 via the arm locking screw 7026. The anchor portion 7032 of thespline ring 7028 extends from a second surface 7038 of the splineportion 7030 generally opposite the spline surface 7036. The anchorportion 7032 and spline portion 7030 define an opening 7040 extendingthrough the spline ring 7028. The anchor portion 7032 can be insertedinto an opening 7042 (see FIGS. 90 and 93) in the light post mount 7002and preferably is secured therein using an epoxy.

FIGS. 98-99 show a viewing element that is similar to the other viewingelements described herein, except as set forth below. With reference toFIGS. 98-99, a light post assembly 7010 preferably comprises a lighttube 7044, a light post mount block 7046, and one or more locator pins7048. The light post assembly 7010 preferably is configured to becoupled with the light post support mount 7002. The light post assembly7010 has a coupler 7050 for connecting the light post assembly 7010 to alight source (not shown). The light tube 7044 preferably is angled todirect light down into a channel or passage of an access device when thelight post assembly 7010 is supported on the light post support mount7002. The light tube 7044 in the illustrated embodiment is about 3 mm indiameter and about 15 mm long. A longer light tube 7044 may be usedwhere it is desired to locate the end 7052 of the light tube 7044farther distally in an access device.

FIGS. 100-106 show a viewing element support block that is similar tothe other viewing element support blocks described herein, except as setforth below. With reference to FIGS. 100-106, the light post mount block7046 is configured to receive and support the light tube 7044, or otherviewing element. In one embodiment, the light post mount block 7046 hasan upper surface 7054 that is contoured for receiving the light tube7044. The light post mount block 7046 can have one or more openings 7056for receiving one or more locator pins 7048. The light post mount block7046 has a notched portion 7058 including a first surface 7060 forcontacting a top surface 7064 (see FIG. 89) of the light post mount 7002and a second surface 7062 for contacting a side surface 7066 of thelight post mount 7002. FIG. 107 shows one embodiment of a locator pin7048. The locator pin 7048 is generally cylindrical, though other shapesmay be used in some embodiments. The locator pin 7048 can be coupledwith the light post mount block 7046 to retain the light post mountassembly 7010 in a desired location on the light post mount 7002.

FIGS. 108-109 show an indexing collar assembly that is similar to theother indexing collar assemblies described herein, except as set forthbelow. With reference to FIGS. 108-109, one embodiment of an indexingcollar assembly 7068 comprises an indexing collar 7070, as shown in moredetail in FIGS. 110-119. The indexing collar assembly 7068 alsopreferably comprises a support arm 7072 or clamp arm, an arm extensionassembly 7074, and an arm locking screw 7076. In the illustratedembodiment, the indexing collar 7070 is configured to be coupled with anaccess device having a proximal portion with a generally oval shapedcross-sectional area. In other embodiments, the indexing collar 7070 canbe configured to be coupled with an access device having any otheroblong shaped cross-sectional area. In one embodiment, the indexingcollar 7070 is configured to be coupled with an access device having aproximal portion that has a generally oval shaped opening that is about24 mm wide and about 30 mm long. In another embodiment, the indexingcollar 7070 is configured to be coupled with an access device having aproximal portion with a generally oval shaped opening that is about 24mm wide and about 35 mm long.

FIGS. 108-119 show an indexing collar that is similar to the otherindexing collars described herein, except as set forth below. Withreference to FIGS. 108-119, in one embodiment, the support arm 7072 iscoupled with an indexing collar 7070, which can be configured to bereceived in a central opening of a base of an endoscope mount platformor other viewing element mount platform, such as shown in FIGS. 20-23.The indexing collar 7070 has an outer peripheral wall surface 7078, aninner wall surface 7080, and a wall thickness 7082 that is the distancebetween the wall surfaces. With reference to FIG. 119, the outerperipheral wall surface 7078 has a generally constant diameter. Theinner wall surface 7080 preferably has a variable diameter resulting ina generally oval shaped cross-sectional area defined by the inner wallsurface 7080. In other embodiments, the inner wall surface 7080 candefine any other oblong shaped cross-sectional area. Accordingly, thewall thickness 7082 varies between the outer peripheral wall surface7078 and the inner wall surface 7080.

In one embodiment, access devices of different shapes and dimensions canbe supported by providing indexing collars to accommodate each accessdevice size while using a single endoscope mount platform. The centralopening of the endoscope mount platform can have a constant dimension,e.g., a diameter of about 1.28 inches (32.5 mm). An appropriate indexingcollar is selected, e.g., one that is appropriately sized to support aselected access device. Thus, the outer wall and the outer diameterpreferably are unchanged between different indexing collars, althoughthe inner wall and the inner diameters of the oval shape can vary toaccommodate differently sized access devices.

The indexing collar 7070 can be positioned at or rested on a proximalportion of an access device to allow angular movement of the endoscopemount platform, or other viewing element mount platform, with respectthereto about the longitudinal axis. In one embodiment, the outer wallof the indexing collar 7070 includes a plurality of hemisphericalrecesses, or through holes 7084, that can receive one or more ballplungers on the endoscope mount platform. This arrangement permits theendoscope mount platform, along with an endoscope, or other viewingelement, to be fixed in a plurality of discrete angular positionsrelative the indexing collar 7070.

FIGS. 120-122 show a dilation element that is similar to the otherdilation elements described herein, except as set forth below. FIGS.120-122 illustrate one embodiment of a dilating structure or tool foruse with an access device. As shown in the illustrated embodiment, acannulated oval dilator 7086 can have an inner surface 7088 that has agenerally circular cross section and an outer surface 7090 that has agenerally oval shaped cross section. In other embodiments, the outersurface 7090 can have any other oblong shaped cross section. The outersurface 7090 preferably provides indications 7092 regarding instrumentdepth. In one embodiment, a proximal portion 7094 of the dilator 7086comprises a gripping portion 7096 to facilitate handling and to aid inthe insertion of the dilator 7086 into a patient. The gripping portion7096 of the dilator 7086, in some embodiments, can have, for example,raised portions or a knurled surface. The dilator 7086 preferably has atapered distal portion.

FIGS. 123-150 illustrate some embodiments of access devices, accessassemblies, and portions of access devices. FIGS. 123-150 show accessdevices that are similar to the other access devices described herein,except as set forth below. With reference to FIGS. 123-124, oneembodiment of an access device 7100 can be positioned in a low-profileconfiguration for insertion into a patient. As shown in FIGS. 123-124,the access device 7100 has a passage 7102 with a generally oval shapedcross section. In one embodiment, the cross section of a proximalportion 7104 of the passage 7102 preferably has a width of about 24 mmand a length of about 30 mm. The cross section of the passage 7102 atthe distal portion 7106 of the access device 7100, in the low profileconfiguration, preferably has a width of about 24 mm and a length ofabout 30 mm. The access device 7100 can be held in a low profileposition using a sleeve 7108 or a length of shrink tubing. A pull string7110 and tab 7112 can be used to at least partially release the shrinktubing from the access device 7100.

FIGS. 125-126 show the access device 7100 in an expanded configuration.In the illustrated embodiment, the access device 7100 has a distalportion 7106 that expands to a cross section at or near the distal endhaving a width of about 24 mm and a length of about 50 mm. In otherembodiments, the sizes and lengths associated with the access device7100 can vary, as will be described further below. The length 7128 ofthe access device 7100 from the proximal end of the proximal portion7104 to the distal end of the distal portion 7106 preferably is betweenabout 2 inches (50.8 mm) and about 5 inches (127 mm). In someembodiments, the length 7128 of the access device 7100, e.g., about 60mm, about 70 mm, about 80 mm, about 90 mm, about 100 mm, about 110, ormore than any of the foregoing dimensions, preferably is selected basedon the anatomy of the patient and/or the type of procedure to beperformed.

With reference to FIGS. 125-129, the proximal portion 7106 of the accessdevice 7100 includes a tube 7114. The distal portion 7106 of the accessdevice 7100 has an expandable skirt portion 7116. The skirt portion 7116preferably has a reduced profile configuration with an initial dimension7118 and corresponding cross-sectional area. The skirt portion 7116preferably is expandable to an enlarged configuration with a relativelylarger dimension 7120 and corresponding cross-sectional area. In oneembodiment, the skirt portion 7116 is coupled with the proximal portion7104. A rivet 7122, pin, or similar connecting device can be used tocouple the proximal and distal portions 7102, 7104. The rivet 7122preferably permits movement of the skirt portion 7116 relative to theproximal portion 7104. The skirt portion 7116 is shown coupled with theproximal portion in FIG. 129.

In the illustrated embodiment, the skirt portion 7116 is manufacturedfrom a resilient material, such as stainless steel. The skirt portion7116 preferably is manufactured so that it normally assumes an expandedconfiguration. The skirt portion 7116 preferably is sufficiently rigidthat it is capable of displacing the tissue surrounding the skirtportion 7116 as it expands. Depending upon the resistance exerted bysurrounding tissue, the skirt portion 7116 preferably is sufficientlyrigid to provide some resistance against the tissue to remain in theexpanded configuration. In some embodiments, one feature of the skirtportion 7116 is the provision of a shallow concave profile 7124 definedalong a distal edge of the skirt portion 7116, which allows for improvedplacement of the skirt portion 7116 with respect to body structures andsurgical instruments. In some embodiments, one or more portions of theskirt portion 7116, e.g., along the distal edge, are formed toaccommodate long implants or tools. For example, cut outs can beprovided on opposite sides of the distal edge of the skirt portion 7116to enable a fixation element to be at least partially extended out ofthe working space.

FIGS. 130-132 further illustrate the proximal portion 7104 of the accessdevice 7100, according to one embodiment. The length 7126 of theproximal portion 7104 of the access device 7100 preferably is betweenabout 1 inch (25.4 mm) and about 4 inches (101.6 mm) in one embodiment.The length 7104 of the proximal portion of the access device, e.g.,about 27 mm, about 37 mm, about 47 mm, about 57 mm, about 67 mm, orabout 77 mm, preferably is selected based on the anatomy of the patientand/or the type of procedure to be performed.

FIGS. 133-134 show distal skirt portions 7116 of the access device 7100according to one embodiment. The size and shape of the skirt portion7116 advantageously provides access to a surgical location when coupledwith the proximal portion of the access device and placed in an expandedconfiguration. In other embodiments, skirt portions 7116 have differentsizes and shapes. In some embodiments, the shape of the distal portion7106 of the access device 7100 can provide an oval shaped access areawhen expanded. In other embodiments, the shape of the distal portion7106 of the access device 7100 can provide any other oblong shapedaccess area when expanded. In some embodiments a locking mechanism 7130is provided on the distal portion 7106 of the access device 7100 as willbe described further below.

FIGS. 133-134 show right and left skirt portions 7148, 7150 in initialflattened configurations. FIG. 133 illustrates a right skirt portion7148 for an access device 7100 with an oval shaped cross section havingan expanded length 7120 of about 50 mm along the long axis. FIG. 134illustrates a cooperating left skirt portion 7150 for the access device7100. The skirt portions 7116 can be manufactured from sheets ofstainless steel having a thickness of about 0.007 inches (0.178 mm).Other materials, such as nitinol or plastics having similar properties,may also be used. The skirt portions 7148, 7150 preferably each have aprotruding portion 7132 along one of the sides for providing a lockingfeature, as will be described further below.

As discussed above, the skirt portions 7148, 7150 are coupled with theproximal portion 7104 with pivotal connections, such as rivets 7122. Afirst rivet hole 7134 and second rivet hole 7136 can be provided in eachof the right and left skirt portions 7148, 7150 to receive the rivets7122. In the illustrated embodiment, the right and left skirt portions7148, 7150 each have first and second free ends 4138, 4140 that aresecured by slidable connections, such as additional rivets 7142. In theillustrated embodiment, a first slot 7144 and a second slot 7146 aredefined in the right skirt portion 7148 near the free ends 7138, 7140respectively. In the illustrated embodiment, a first slot 7152 and asecond slot 7154 are defined in the left skirt portion 7150 near thefree ends 7138, 7140 respectively. With reference to FIGS. 133-134, inone embodiment, the first slots 7144, 7152 preferably are longer thanthe second slots 7146, 7154. The right and left skirt portions 7148,7150 preferably are configured so that a rivet 7142 that is positionedwithin the longer slot 7144 in the right skirt portion 7148 ispositioned in the shorter slot 7154 in the left skirt portion 7150.Similarly, a rivet 7142 that is positioned within the longer slot 7152in the left skirt portion 7150 is positioned in the shorter slot 7146 inthe right skirt portion 7148. The rivets 7142 are permitted to movefreely within the slots 7144, 7154, 7152, 7146. This slot and rivetconfiguration allows the skirt portions 7148, 7150 to move between thereduced profile configuration of FIGS. 123-124 and the expandedconfiguration of FIGS. 125-129. The skirt portion 7116 preferably canexpand to span up to three or more vertebrae, e.g., L4, L5, and S1. Thisarrangement enables multi-level procedures, such as multilevel fixationprocedures alone or in combination with a variety of other procedures.One of the rivets 7142 coupling the left and right skirt portions 7148,7150 together, along with a pair of washers 7156, is shown in FIG. 128.

In the illustrated embodiment, the access device 7100 has a lockingmechanism 7130. The distal portion 7106 is provided with a lock thatenables a user to selectively lock the distal portion 7106 into a stateof expansion. In some embodiments, the user can lock the distal portionin a contracted configuration. In the illustrated embodiment, a firstlocking mechanism 7130 is provided on a first side of the access device7100. A second locking mechanism preferably is provided on a second sideof the access device 7100. The locking mechanism 7130 can take manyforms. In one embodiment, the locking mechanism 7130 includes a firstlocking slot 7160, a second locking slot 7162, and a clip or lockingelement 7164 that can be moved (e.g., rotated, actuated, manipulated) tolock the access device 7100 in a desired configuration. In theillustrated embodiment, first and second locking slots 7160, 7168 aredefined in the right skirt portion 7148 near the free ends 7138, 7140.In the illustrated embodiment, first and second locking slots 7166, 7162are defined in the left skirt portion 7150 near the free ends 7138,7140. With reference to FIGS. 133-134, the first locking slots 7160,7166 preferably are longer than the second locking slots 7162, 7168. Thelonger slots 7160, 7166 preferably are curved or angled near an end ofthe slots. The shorter slots 7162, 7168 preferably are also curved. Inone embodiment, each of the shorter slots 7162, 7168 generally forms anarc. The right skirt portion 7148 has an opening 7170 positioned nearthe shorter slot 7168. The left skirt portion 7150 has an opening 7172positioned near the shorter slot 7162. The shorter curved slots 7162,7168 preferably are formed on or near protruding portions 7132 of theskirts.

FIGS. 135-137 illustrate a locking clip or locking element 7164,according to one embodiment. With reference to FIGS. 135-137, a lockingelement 7164, e.g., a lock, a stop, a tab, a flange, a clip, or a hook,preferably is coupled with one or more of the left and right skirtportions 7148, 7150. In the illustrated embodiment, the locking element7164 has a generally L-shaped configuration. The locking element 7164preferably is movable, e.g., rotatable, articulable, manipulatable, orpositionable, relative to one or more of the skirt portions 7148, 7150.As shown in FIGS. 135-137, the locking element has a base portion 7174,a tab portion 7176, and a disk portion 7178. The base portion 7174preferably has a length of about 0.21 inches (5.33 mm) and a thicknessof about 0.0155 inches (0.394 mm) in one embodiment. An opening 7180 isdefined in the base portion 7174. The opening 7180 preferably is sizedto receive a coupling member, such as, for example, a rivet 7182. In theillustrated embodiment, the opening 7180 preferably has a diameter ofabout 0.046 inches (1.17 mm). In some embodiments the opening 7180 canbe located generally centrally on the base portion 7174. The diskportion 7178 preferably extends from a first surface 7184 of the baseportion 7174. In the illustrated embodiment, the disk portion 7178extends from the first surface 7184 a distance of about 0.0155 inches(0.394 mm) and has a diameter of about 0.04 inches (1.02 mm). The diskportion 7178 preferably is positioned near a first end of the baseportion 7174. In some embodiments, the disk portion 7178 can be weldedto the base portion 7174. In the illustrated embodiment, the tab portion7176 is positioned generally normal to the base portion 7174 near asecond end of the base portion 7174. The tab portion 7176 preferablyextends about 0.055 inches (1.40 mm) from a second surface 7186 of thebase portion 7174 and has a thickness of about 0.0155 inches (0.394 mm).In one embodiment, the locking element 7164 is made of stainless steel.In some embodiments, the locking element 7164 can be fabricated bymachining or formed and welded.

With reference to FIGS. 125-127 and 133-134, in one embodiment, thelocking mechanism 7130 comprises the right and left skirt portions 7148,7150, the locking element 7164, one or more compression washers 7188(See FIGS. 127 and 138) and a rivet 7182. The locking element 7164preferably is coupled with the right skirt portion 7148 at the opening7170 on or near the protruding portion 7132 of the skirt using the oneor more compression washers 7188 and the rivet 7182. The locking element7164 preferably is positioned between the right and left skirt members7148, 7150 and oriented such that the first surface 7184 of the baseportion 7174 of the locking element 7164 faces toward the right skirtportion 7148. The disk portion 7178 preferably is positioned to facetoward the smaller arcuate slot 7168 on the protruding portion 7132 ofthe right skirt portion 7148. The locking element 7164 is sized andconfigured so that when the locking rivet 7182 is positioned in theopening 7180 of the locking element 7164 and also in the opening 7170 onthe right skirt portion 7148, the disk portion 7178 of the lockingelement 7164 can be positioned so that it extends into the smallerarcuate slot 7168 on the right skirt portion 7148. In the illustratedembodiment, the disk portion 7178 is oriented such that the disk portion7178 faces toward the outside of the access device 7100. The accessdevice 7100 preferably is also configured so that when the slidingrivets 7142 coupling the right and left skirt portions 7148, 7150 arepositioned within the appropriate slots, e.g., the rivet 7142 withinslots 7144 and 7154, the tab end 7176 of the locking mechanism 7130 canextend toward, and be positioned within, the longer curved or angledslot 7166 on the left skirt portion 7150. In the illustrated embodiment,the tab portion 7176 extends toward the inside of the access device7100. The locking element 7164 preferably is rotatably coupled with theright skirt portion 7148 at the opening 7170 with the one or morecompression members 7188 and the rivet 7182, as shown in FIG. 127.

When the access device 7100 is in the closed position, or the lowprofile position, the locking element 7164 preferably is rotated so thatthe tab portion 7176 is positioned within the longer portion of thelonger curved or angled slot 7166. In this configuration, the right andleft skirt portions 7148, 7150 are free to slide past one another intothe expanded configuration. When the access device 7100 is in theexpanded configuration, the tab portion 7176 of the locking element 7164can be rotated into the shorter curved or angled portion of the longerslot 7166. The locking element 7164 can be actuated, manipulated, orrotated using an instrument or in any other suitable manner to positionthe tab portion 7176 in the angled portion of the slot 7166. When thetab portion 7176 is engaged in the locked position, the sides of thecurved or angled portion of the longer slot 7166 act to restrain therelative movement of the overlapping skirt portions 7148, 7150 toselectively limit expansion or un-expansion of the distal portion 7106of the access device 7100. In some other embodiments, the relative sizesand configurations of the locking structures and mechanisms can vary.

In one application, the access device 7100 is used to provide minimallyinvasive access to the spine for a spinal procedure as described herein.The expansion and location of the access device 7100 may be confirmed byfluoroscopy. After the access device 7100 has been fully expanded, thelock can be articulated to lock or unlock the access device 7100.

FIGS. 139-150, illustrate another embodiment of an access device 7200.The structure and configuration of the access device shown in FIGS.139-150 is similar to that described in connection with FIGS. 123-138,except as shown or noted below. Like reference numerals have been usedto identify like features in the two embodiments, except that thereference numerals used with respect to FIGS. 139-150 will be in the“7200s” rather than the “7100s.”

As shown in FIGS. 139-150, the access device 7200 has a passage 7202with a generally oval shaped cross section. FIGS. 141-142 show theaccess device 7200 in an expanded configuration. In the illustratedembodiment, the access device 7200 has a distal portion 7206 thatexpands to a cross section having a width of about 24 mm and a length7220 of about 80 mm. The sizes and lengths associated with the accessdevice 7200 can vary. In some embodiments, a generally longercross-sectional length provides increased access for performing somesurgical procedures. FIGS. 149-150 show distal skirt portions 7216 ofthe access device 7200 according to one embodiment. The size and shapeof the skirt portion 7216 advantageously provides increased access to asurgical location in an expanded configuration. In other embodiments,skirt portions 7216 have different sizes and shapes. In someembodiments, the shape of the distal portion 7206 of the access device7200 can provide an oblong shaped access area when expanded. FIGS.149-150, show right and left skirt portions 7248, 7250 in initialflattened configurations. In the illustrated embodiment, the skirtportions 7248, 7250 are configured to form an access device 7200 havingan oval shaped cross section with an expanded length 7220 of about 80 mmalong the long axis. In the illustrated embodiment, a locking mechanism7230 generally similar to that described with respect to the embodimentshown in FIGS. 123-138 is provided.

FIGS. 151-181 illustrate surgical systems that may include a device forproviding minimally invasive access at a surgical site and a variety oftools that can be used to perform various procedures at the surgicalsite. FIGS. 151-181 show surgical systems and components that aresimilar to the other surgical systems and components described herein,except as set forth below. Also disclosed are a number of components,e.g., implants, that may be applied to the spine at various spinallocations in connection with such procedures. A variety of advantageouscombinations may be provided whereby features of these embodiments arecombined with features of other embodiments described herein.

One embodiment of a surgical system described herein is particularlywell suited for performing various methods for fixing the vertebrae of apatient at a surgical site. As discussed more fully herein, a surgicalsystem can include an access device, such as an expandable cannula orconduit, an adjustable support for the access device, a variety ofsurgical instruments, a viewing device, a lighting element, a spinalimplant or fusion device, and a vertebral fixation assembly. Many ofthese components, e.g., the instruments, viewing device, spinalimplants, and fixation assembly components, preferably are configured tobe inserted through the access device to the surgical site.

FIGS. 151-155 illustrate one suitable expandable cannula or conduit 8010constructed for use in a method according to one embodiment. The cannula8010 is a tubular structure 8012 centered on an axis 8014. The tubularstructure 8012 defines a passage 8016 through the cannula 8010. Surgicalinstruments are inserted into the body during surgery through thepassage 8016.

The tubular structure 8012 comprises a first tubular portion 8020 and asecond tubular portion 8040 attached to the first tubular portion. Thefirst tubular portion 8020 is preferably made of a length of stainlesssteel tubing, but could alternatively be made of another suitablematerial. The first tubular portion 8020 has a proximal end 8022 and adistal end 8024. Parallel cylindrical inner and outer surfaces 8026 and8028, respectively, extend between the ends 8022, 8024 of the firsttubular portion 8020. The inner surface 8026 defines a first passageportion 8030 of the passage 8016 through the cannula 8010. The firstpassage portion 8030 has a diameter D1 that is preferably in the rangefrom 10 mm to 30 mm.

The second tubular portion 8040 of the tubular structure 8012 isattached to the distal end 8024 of the first tubular portion 8020. Thesecond tubular portion 8040 is preferably made from stainless steel, butcould alternatively be made from another suitable material.

As best seen in the rollout view of FIG. 154, the second tubular portion8040 comprises an arcuate segment 8042 of sheet stock. The arcuatesegment 8042 includes first and second arcuate edges 8044 and 8046,respectively, and first and second planar edges 8048 and 50,respectively. The first and second planar edges 8048 and 8050 are rolledin an overlapping manner to form the tubular configuration of the secondtubular portion 8040.

When the second tubular portion 8040 has been rolled into its tubularconfiguration, the first and second arcuate edges 8044 and 8046 defineoppositely disposed first and second ends 8060 and 8062 (FIGS. 151-152),respectively, of the second tubular portion. The first and second ends8060 and 8062 are connected by a central portion 8064. The first end8060 of the second tubular portion 8040 is attached to the distal end8024 of the first tubular portion 8020 by a single fastener, such as arivet 8066. The rivet 8066 extends through two aligned apertures 8068(FIG. 154) at the first end 8060 of the second tubular portion 8040. Thefirst end 8060 of the second tubular portion 8040 is pivotable about therivet 8066.

The second tubular portion 8040 includes parallel inner and outersurfaces 8070 and 8072 (FIGS. 151-152), respectively, extending betweenthe first and second ends 8060 and 8062. The inner surface 8070 definesa second passage portion 8074 of the passage 8016 through the cannula8010 that extends as a continuation of the first passage portion 8030 inthe first tubular portion 8020.

An arcuate slot 8080 is formed in the second tubular portion 8040 andextends between the inner and outer surfaces 8070 and 8072 of the secondtubular portion. The arcuate slot 8080 extends along a curvilinear pathin the central portion 8064 of the second tubular portion 8040 towardthe second end 8060 of the second tubular portion. The arcuate slot 8080has a first terminal end 8082 located in the central portion 8064 of thesecond tubular portion 8040. A second terminal end 8084 of the arcuateslot 8080 is located adjacent the intersection of the second arcuateedge 8046 and the first planar edge 8048 of the arcuate segment 8042.

A guide pin 8090 is attached to the inner surface 8070 of the secondtubular portion 8040 adjacent the intersection of the second arcuateedge 8046 and the second planar edge 8050. In the tubular configurationof the second tubular portion 8040, the guide pin 8090 is located in thearcuate slot 8080 and is movable along the curvilinear path of thearcuate slot. A washer 8092 is secured to an inner end of the guide pin8090 to retain the guide pin in the arcuate slot 8080.

The second tubular portion 8040 of the tubular structure 8012 isexpandable from a contracted condition shown in FIG. 152 to an expandedcondition shown in FIG. 151. In the contracted condition, the guide pin8090 is located in the first terminal end 8082 of the arcuate slot 8080in the second tubular portion 8040 and the second passage portion 8074defined by the second tubular portion is cylindrical in shape. Thesecond passage 8074 has a generally constant diameter D2 (FIGS. 152-153)that is approximately equal to the diameter D1 of the first tubularportion 8020. Thus, the cross-sectional area of the second passageportion 8074 at the second end 8062 of the second tubular portion 8040,which is function of the diameter D2, is approximately the same as thecross-sectional area at the first end 8060 of the second tubular portionand is approximately the same as the cross-sectional area of the firstpassage portion 8030 in the first tubular portion 8020.

In the expanded condition, the guide pin 8090 is located in the secondterminal end 8084 of the arcuate slot 8080 in the second tubular portion8040 and the second tubular portion has a conical configuration. At thesecond end 8062 of the second tubular portion 8040, the second passageportion 8074 has a diameter D3 (FIG. 153) that is larger than thediameter D2 of the second passage portion at the first end 8060.Preferably, the diameter D3 of the second passage portion 8074 at thesecond end 8062 of the second tubular portion is 40% to 80% greater thanthe diameter D1 of the second passage portion at the first end 8060.Thus, in the expanded condition, the cross-sectional area of the secondpassage portion 8074 at the second end 8062 of the second tubularportion 8040, which is function of the diameter D3, is 16% to 64%greater than the cross-sectional area of the second passage portion atthe first end 8060 of the second tubular portion. In the expandedcondition, the cross-sectional area of the second passage portion 8074at the second end 8062 of the second tubular portion 8040 is largeenough to overlie a major portion of at least two adjacent vertebrae.

The cannula 8010 includes an outer layer 8100 (FIG. 151) for maintainingthe second tubular portion 8040 of the cannula in the contractedcondition. It is contemplated that other suitable means for maintainingthe second tubular portion 8040 in the contracted condition could beemployed. In accordance with a preferred embodiment of the presentinvention, the outer layer 8100 comprises a section of plastic tubing8102 which is heat shrunk over both the first and second tubularportions 8020 and 8040 to hold the second tubular portion in thecontracted condition.

In addition, a loop of polyester string 8104 for tearing the heat shrunktubing 8102 is wrapped around the heat shrunk tubing so that it extendsboth underneath and on top of the tubing. An outer end 8106 of thestring 8104 extends beyond the tubing 8102.

FIG. 151 shows an actuatable device 8111 for expanding the secondtubular portion 8040 from the contracted condition to the expandedcondition. In accordance with a preferred embodiment, the actuatabledevice 8111 comprises a manually operated expansion tool 8112. Theexpansion tool 8112 resembles a common pair of scissors and has a pairof legs 8114 pivotally connected to one another. The expansion tool 8112includes a frustoconical end section 8116 formed by a pair offrustoconical halves 8118. Each of the frustoconical halves 8118 extendsfrom a respective one of the legs 8114 of the expansion tool 8112. It iscontemplated that other suitable means for expanding the second tubularportion 8040 toward the expanded condition could be employed, such as aninflatable balloon (not shown).

During an endoscopic surgical procedure, the cannula 8010 is insertedinto the body of a patient in the contracted condition. The outer end8106 of the string 8104 is then manually pulled on by the surgeon.Pulling on the string 8104 tears the heat shrunk tubing 8102 most of theway along the heat shrunk tubing, which frees the second tubular portion8040 for expansion. The heat shrunk tubing 8102, in its torn condition,remains attached or secured to the first tubular portion 8020.

Next, the expansion tool 8112 is inserted into the passage 8016 in thecannula 8010 until the frustoconical end section 8114 is located at thesecond end 8062 of the second tubular portion 8040. The legs 8114 of theexpansion tool 8112 are manually separated, causing the frustoconicalhalves 8118 to separate also. As the halves 8118 separate, a radiallyoutward directed force is exerted on the inner surface 8070 of thesecond tubular portion 8040 by the halves 8118, causing the secondtubular portion to expand toward the expanded condition. Under the forceof the expanding expansion tool 8112, the guide pin 8090 slides from thefirst terminal end 8082 of the arcuate slot 8080 to the second terminalend 8084 of the arcuate slot to permit the expansion of the secondtubular portion 8040. The expansion tool 8112 can be rotated about theaxis 8014 to ensure that the second tubular portion 8040 of the cannula8010 is completely expanded to the expanded condition. The expansiontool 8112 is then collapsed and removed so that one or more surgicalinstruments (indicated schematically at 8021 in FIG. 155) and a viewingelement can be received through the cannula 8010 and inserted into apatient's body 8130. The expandable second tubular portion 8040 of thecannula 8010 provides a significantly larger working area for thesurgeon inside the body 8130 within the confines of the cannula.

The expanded tubular portion 8040 can dilate and locally retract andseparate spinalis muscle and soft tissues from the vertebrae therebycreating an endoscopic operating field at the surgical site. Thisendoscopic operating field within the spinal muscles differs fromarthroscopic, laparoscopic, or cystoscopic working spaces in that thereis no physiologic space or defined tissue plane that can be insufflatedwith air or distended with fluid.

FIGS. 156-173 illustrate one suitable support apparatus for use in amethod according to one embodiment. The support apparatus 8110 includesa first support 8120, a second support 8140, a first adjustmentmechanism 8160, a second adjustment mechanism 8180, and a thirdadjustment mechanism 8900.

As viewed in FIGS. 159 and 165, the first support 8120 is associatedwith the cannula 8010 and has a circular perimeter 8121. The perimeter8121 has a center 8122 located on the axis 8014. The first support 8120comprises a circular platform, or disk 8124, which has a circularopening 8126 in the central area of the disk 8124 for receiving theproximal end 8022 of the cannula 8010. The circular opening 8126 has acenter located on the axis 8014. The proximal end 8022 of the cannula8010 can be easily inserted into and removed from the opening 8126. Thedisk 8124 has a projection portion 8120 a, which is located adjacent theperimeter 8121 of the disk 8124. The disk 8124 has an upper circularsurface area 8124 a, which surrounds the opening 8126.

As viewed in FIG. 165, the second support 8140 supports a viewing device8200 including a camera head 8201 and an endoscope 8202 with a rod andlens assembly 8203, herein referred to as a viewing element, extendingdown through the passage 8016 of the cannula 8010. With reference toFIGS. 165-166, the second support 8140 includes a body 8142 having anopening 8144 through which the viewing device 8200 extends and a clamp8146 for clamping the viewing device 8200 to the body 8142 in theopening 8144. The clamp 8146 includes a threaded set screw 8148 forsecuring the viewing device 8200 to the body 8142. The set screw 8148has a manually rotatable knob 8148 a and a stem threaded into the body8142. When rotated, the screw 8148 moves axially relative to the body8142 to clamp or release the viewing device 8200 depending on thedirection of rotation of the screw 8148.

The body 8142 of the second support 8140 further includes two extensionarms 8151, 8152 (FIG. 158) for supporting the endoscope 8202. Eachextension arm 8151, 8152 includes a threaded bore for receiving aresilient detent member, or ball plunger 8400.

As viewed in FIGS. 167-168, a ball plunger 8400 is illustrated atanother location in the support apparatus 8110. Each ball plunger 8400,including those in the extension arms 8151, 8152, has an externallythreaded tubular body 8402 with a cylindrical cavity 8404 locatedtherein. The cavity 8404 houses a projection 8406 and a coiled spring8408. The projections 8406 of the two ball plungers 8400 of theextension arms 8151, 8152 are spherical detent members 8420 in the formof balls (not shown). The spring 8408 urges each projection 8406 againsta lip portion 8409 of the body 8402. The lip portion 8409 is located atone end of the cavity 8404. As shown in FIG. 168, the other ballplungers 8400 of the apparatus 8010 have projections 8406 withhemispherical extensions 8420 and shoulder portions 8422.

As viewed in FIG. 165, the endoscope 8202 has correspondinghemispherical recesses (not shown) for receiving the spherical detentmembers (balls) of the ball plungers 8400 which are located in extensionarms 8151, 8152. The springs 8408 will compress in each ball plunger8400 in each extension arm 8151, 8152 and the spherical detent memberswill move inward of each cavity 8404 and then spring back into thehemispherical recesses in the endoscope 8202, as the endoscope 8202 isinserted between the extension arms 8151, 8152. The entire viewingdevice 200 will thus be secured between the extension arms 8151, 8152,but may be removed by overcoming the force of the spherical detentmembers of each ball plunger 8400 in the extension arms 8151, 8152.

The ball plunger 8400 further includes a head portion 8430 with a slot8432 for engaging a tool, such as a screwdriver. The ball plunger 8400may be threadedly adjusted within the threaded bore of either extensionarm 8151, 8152 to alter the distance that the spherical detent member8420 projects away from the extension arms 8151, 8152 (toward eachother). This distance, along with the stiffness of each spring 8408,will determine the holding force by which the endoscope 8202 is securedbetween the extension arms 8151, 8152.

The first adjustment mechanism 8160 provides for relative axialadjustment of the cannula 8010 and the first support 8120 along the axis8014. The first adjustment mechanism 8160 includes a first toothed rackmember 8162, a cannula gripper mechanism 8164 fixedly connected to thefirst rack member 8162, a first manually adjustable, rotatable knob 8166rotatably carried by the projection portion 8120 a of the first support8120, and a first gear member 8165 (FIG. 162) rotatable by the firstknob 8166 and in meshing engagement with the teeth 8163 of the firstrack member 8162. The first support 8120 and, in particular, theprojection portion 8120 a, rotatably carries the first gear member 8165(FIG. 162).

The first rack member 8162 is secured to slide axially within the firstsupport 8120 and the projection portion 8120 a by two ball plungers 8400(FIG. 162). One ball plunger 8400 is tangentially threaded into atapered, threaded bore (FIG. 157) in the perimeter 8121 of the firstsupport 8120 and the other is tangentially threaded into a threaded borein the projection portion 8120 a. The hemispherical extensions 8420 thusfrictionally engage a smooth portion (without teeth 8163) of the firstrack member 8162 and bias the first rack member 8162 against the firstsupport 8120 and the projection portion 8120 a. This biasing alsomaintains the engagement of the first rack member 8162 and the firstgear member 8165 (FIG. 162).

As viewed in FIGS. 160 and 169, the cannula gripper mechanism 8164includes two gripper arms 8172, 8174 for clamping against the outersurface of the cannula 8010, and a gripper actuating lever 8176 formoving the arms 8172, 8174 into engagement with the outer surface of thecannula 8010 and for releasing the arms 8172, 8174 from engagement withthe cannula 8010.

As viewed in FIG. 169, the cannula gripper mechanism 8164 furtherincludes a support pin 8177, a coiled spring 8188, a washer 8189 with abore (not shown), and a lock pin 8190. The support pin 8177 has a head8179, a shaft 8180, and an elongate, or flat, end 8181 that can matewith the bore in the washer 8189. Other suitable structures could beused.

During assembly, the coiled spring 8188 is interposed between the arms8172, 8174. The flat end 8181 of the support pin 8177 is insertedthrough a circular bore in the first clamp arm 8172, through the coil ofthe spring 8188, through a circular bore in the second arm 8174, andthrough the bore in the washer 8189. The flat end 8181 of the supportpin 8177 is then inserted into a slot 8176 a in the lever 8176. The lockpin 8190 is inserted through a bore in the lever 8176 and through a borein the flat end 8181 of the support pin 8177 thereby securing themechanism 8164 together and allowing the lever 8176 to rotate about thelock pin 8190. A camming surface 8178 on the lever 8176 adjacent thewasher 8189 forces the arms 8172, 8174 together to grip the cannula 8010as the lever 8176 is rotated clockwise (as viewed in FIG. 160).Counterclockwise rotation of the lever 8176 allows the spring 8188 toforce the arms 8172, 8174 apart and releases the cannula 8010 from thegripper mechanism 8164.

When the gripper mechanism 8164 is either gripping the cannula 8010 orreleased from the cannula 8010 and the knob 8166 is rotated, the disk8124 and parts attached to the disk 8124 will move along the axis 8014of the cannula 8010 relative to the cannula 8010. After the supportapparatus 8110 is initially lined up with the cannula 8010, the viewingdevice 8200 may be positioned on the support apparatus 8110 and adjustedalong the axis 8014 by rotation of knob 8166.

The second adjustment mechanism 8180 provides axial adjustment of thefirst and second supports 8120, 8140 relative to each other along theaxis 8014. The second adjustment mechanism 8180 includes a secondtoothed rack member 8182 connected to the first support 8120, a secondmanually adjustable, rotatable knob 8186 rotatably carried by the body8142 of the second support 8140, and a second toothed gear member 8185(FIG. 163) rotatable by the second knob 8186 and in meshing engagementwith the teeth 8183 of the second rack member 8182. The second support8140, and in particular, the body 8142, rotatably carries the secondgear member 8185 (FIG. 163).

The body 8142 of the second support 8140 may have a notch 8149 which canfit around part 8902 a of the third adjustment mechanism 8900 and allowthe lower surface of the body 8142 to completely abut the disk 8124 asthe body 8142 is brought into an axial position adjacent the disk 8124.

The second rack member 8182 is secured to slide axially within thesecond support 8140 by a ball plunger 8400 (FIG. 163). The ball plunger8400 is tangentially threaded into a threaded bore in the side of thenotch 8149 of the second support 8140. The hemispherical extension 8420thus frictionally engages a smooth portion (without teeth 8183) of thesecond rack member 8182 and biases the second rack member 8182 againstthe second support 8140. The biasing also maintains the engagement ofthe second rack member 8182 and the second gear member 8185. Both sidesof the notch 8149 have tapered portions 8149 a, 8149 b for facilitatinginsertion of the ball plunger 8400 into the threaded bore of the notch8149 of the second support 8140. Rotation of the knob 8186 causes thebody 8142 and the viewing device 8200 attached thereto to move relativeto the cannula 8010 and disk 8124 along the axis 8014.

The third adjustment mechanism 8900 provides arcuate, circumferentialadjustment of the second support 8140 about the axis 8014 relative tothe first support 8120. The third adjustment mechanism 8900 includes awedge-shaped support member 8902 (FIG. 159) fixedly connecting thesecond rack member 8182 to a ring member 8904 that is rotatablysupported by the first support 8120 and rotatable about the axis 8014relative to the first support 8120 (FIG. 167).

The third adjustment mechanism 8900 further includes a third manuallyadjustable, rotatable knob 8906 that is part of a set screw. The setscrew is rotatably threaded into a projection portion 8902 a of thesupport member 8902 and is engageable with the circular perimeter 8121of the disk 8124 of the first support 8120 to lock the support member8902 in an arcuate position relative to the first support 8120 and theaxis 8014.

As viewed in FIGS. 167-168, the ring member 8904 is supported within acylindrical, open ended recess 8905 of the first support 8120. Therecess 8905 is concentric about the axis 8014. The perimeter 8904 a ofthe ring member 8904 has a groove 8904 b for engaging a plurality ofball plungers 8400 (preferably four equally spaced apart) in the firstsupport 8120. Each of these ball plungers 8400 is similar inconstruction. Each ball plunger 8400 is threaded radially into theperimeter 8121 of the first support 8120 to provide a hemisphericalextension 8420 extending into the recess 8905 of the first support 8120.

The ring member 8904 thus is biasingly supported within the recess 8905of the first support 8120 and can rotatably slide within the recess 8905about the axis 8014. The ball plungers 8400 operatively support the ringmember 8904 in the recess 8905 of the first support 8120. The ringmember 8904, along with the second support 8140 and the second and thirdadjustment mechanisms 8180, 8900, can be easily removed from the recess8905 for cleaning, maintenance, etc. of the parts by overcoming theforce applied by the ball plungers 8400 to the ring member 8904. Whenthe knob 8906 is rotated to disengage the perimeter 8121 of disk 8124,the body 8142 and parts connected thereto can be manually rotated aboutthe axis 8014. This causes the viewing device 8200 to rotate about theaxis 8014 of the cannula 8010 and enables the surgeon to view differentparts of the surgical sight as desired.

As viewed in FIG. 166, the fixed connections of the first rack member8162 to a support arm 8300, the second rack member 8182 to thewedge-shaped support member 8902, and the support member 8902 to thering member 8904 may be made by one or more suitable metal fasteners8290, such as rivets or bolts. The entire support apparatus 8110 can beconstructed from metal or any other suitable material having sufficientmechanical strength and durability. Certain parts may be made frommaterials permitting X-rays and other techniques for viewing thesurgical sight (i.e., radiolucent parts). Other parts may also be madefrom non-magnetic materials to reduce electromagnetic interference(i.e., electromagnetic insulating parts).

With reference to FIGS. 160 and 172, the gripper's arms 8172, 8174 are apart of the support arm 8300 for attaching the support apparatus 8110 toa mechanical robotic arm 8301. The support arm 8300 includes an armportion 8302 that is formed integrally with the arms 8172, 8174. Thearms 8172, 8174 are integrally constructed with the arm portion 8302.

The support arm 8300 also includes an arm portion 8303. The arm portion8303 has an attaching structure 8304, including a groove 8305, whichsnaps into a socket in the mechanical arm 8301. Detents of any suitabletype and designated 8306 in the mechanical arm 8301, hold the armportion 8303 in position in the socket in the mechanical arm 8301. Thedetents 8306 may be controlled by external actuation levers (not shown)on the mechanical arm 8301 for manually releasing the arm portion 8303from the mechanical arm 8301.

The arm portions 8302 and 8303 are pivotally connected to each other bya fastener 8310. The fastener 8310 extends through an opening 8311 inthe arm portion 8302 and threads into a threaded opening 8312 in the armportion 8303. When the fastener 8310 is released, the arm portions 8302,8303 may pivot relative to each other about a pivot axis 8314. The pivotaxis 8314 is centered on the axis of the fastener 8310 and the axis ofthe threaded opening 8312. When the fastener 8310 is tightly screwedinto the threaded opening 8312, the arm portions 8302, 8303 are securedtogether against pivoting movement. When the fastener is released, thearm portions 8303, 8302 may pivot relative to each other about the axis8314.

The end of the arm portion 8302, which is adjacent to the arm portion8303, has a convex surface 8350, which is curved about the axis 8314.The arm portion 8303 has a concave surface 8351, which is also curvedabout the axis 8314. The surfaces 8350, 8351 move concentricallyrelative to each other when the arm portions 8303 and 8302 pivotrelatively about the axis 8314.

The arm portion 8303 has a set of teeth 8320 which encircle the axis8314 and which project axially toward a set of teeth 8321 on the armportion 8302. The teeth 8321 project axially toward the teeth 8320. Theteeth 8320 and the teeth 8321 mesh with each other and provide a lockingaction so that the arm portions 8302, 8303 are positively locked againstrelative movement about axis 8314 when the fastener 8310 is tightlyscrewed into the opening 8312. The teeth 8320, 8321 comprise a lockwhich blocks relative rotation of the arm portions 8302, 8303 about theaxis 8314. When the fastener 8310 is loosened, the arm portions 8302,8303 may be rotated relative to each other about the axis 8314, andthus, the arm portions 8302, 8303 may pivot relative to each other toadjust the position of the support apparatus 8110.

A cylindrical projection 8325 is welded to the arm portion 8303. Thus,the projection 8325 and arm portion 8303 are fixedly connected together.The projection 8325 is centered on the axis 8314 and contains a chamber8328.

As viewed in FIG. 170, the chamber 8328 communicates with a fluidpassage 8329 in a male fluid connector 8331. The male connector 8331attaches to a male connector 8333 on the mechanical arm 8301 by means ofa flexible hose 8392 so that the fluid passage 8329 communicates with afluid passage in the mechanical arm 8301.

As viewed in FIG. 170, the chamber 8328 is closed at its upper end by acap 8335. The cap 8335 has an opening 8336 centered on the axis 8314.The opening 8336 communicates with the chamber 8328. A manually movableinternal valve member 8340 normally closes the opening and blocks thechamber 8328 from communicating with the ambient air surrounding thesupport arm 8300. The valve member 8340 is connected to a stem 8341,which is also centered on the axis 8314. The stem 8341 has a knob orbutton 8343 on its end that may be manually depressed to move the stem8341 and valve member 8340 downward into the chamber 8328. When the stem8341 and valve member 8340 are so moved, the chamber 8328 is incommunication with the ambient air surrounding the device due to theunblocking of the opening 8336.

The mechanical arm 8301 includes relatively movable parts, which permitmovement and adjustment of the support apparatus 8110 in a variety inplanes, directions, and orientations. The mechanical arm 8301 permitseasy movement when a vacuum is not applied to the arm 8301. When avacuum is applied to the arm 8301, relative movement of the parts of thearm 8301 is resisted, and therefore adjustment of the support apparatus8110 is difficult.

When the button 8343 is depressed, the chamber 8328 loses its vacuum andthe pressure in the chamber 8328 increases toward ambient pressure. Thepassage 8329 communicates this pressure increase to the mechanical arm8301, and thus the parts of the mechanical arm 8301 are free to move andallow for adjustment of the position of the support apparatus 8110 bythe surgeon.

Accordingly, when the surgeon uses the support apparatus 8110, thesupport arm 8300 is snapped into the socket of the mechanical arm 8301where it is held by the detent 8306. The surgeon may then depress thebutton 8343 and relatively move parts of the mechanical arm 8301, aswell as the support apparatus 8110 into the position where the surgeondesires the support apparatus 8110 to be. This position may be where theopening 8126 in the disk 8124 is aligned with the proximal end 8016 ofthe cannula 8010 that has been positioned in the patient's body with thedistal end 8024 of the cannula 8010 being located in an incision in thebody of the patient. The viewing device 8200 may be mounted on thesupport apparatus 8110, and the surgeon may make adjustments prior toand during the surgical procedure as desired, as described above.

As viewed in FIG. 173, the support apparatus 8110 may include a secondsupport with a fourth adjustment mechanism 8500 for rotating the viewingdevice 8200 about an axis 8501 (FIG. 165) defined by the ball plungers8400 of the extension arms 8151, 8152 when set screw 8148 is notclamping the viewing device 8200 to the body 8142. The axis 8501 isoffset from the axis 8014 of the cannula 8010 and perpendicular to theaxis 8014 of the cannula 8010. Rotation of the viewing device 8200 aboutaxis 8501 causes the endoscope 8200 and the rod and lens assembly 8203to move perpendicular to the axis 8014 of the cannula 8010. Thisrotation will result in radial adjustment of the position of the rod andlens assembly 8203 in a radial direction transverse to the axis 8014.

The spring-loaded connections of the spherical detent members 8420 ofthe ball plungers 8400 and the hemispherical recesses of the endoscope8202 allow rotation about the axis 8501 when the set screw 8148 isreleased from clamping engagement of the viewing device 8200.

The mechanism 8500 includes a threaded bore 8510 in the second support8140 and an adjustable member 8520 for moving (vertically as viewed inthe figures) a part of the viewing device 8200 about the axis 8501. Theadjustable member 8520 has a rounded first end portion 8522, a threadedmiddle portion 8524, and a knurled second end portion 8526, or knob. Thebore 8510 extends at an angle as shown in FIG. 173 from a lower portionof the second support 8140 up to the opening 8144 in the clamp 8146 ofthe second support 8140.

The adjustable member 8520 is rotated and threaded into the bore 8510and may be rotated until the first end portion 8522 protrudes into theopening 8144 of the second support 8140. Accordingly, when the surgeonwishes to adjust the rod and lens assembly 8203 (within the surgicalsight) about the axis 8501 and radially relative to the axis 8014 of thecannula 8010, the surgeon may loosen the connection of the set screw8148 with the viewing device 8200 and rotate the adjustable member 8520by manually rotating knob 8526 so that the first end portion 8522vertically extends farther or less into the opening 8144. Thisadjustment will adjust the part of the viewing device 8200 engaged bythe clamp 8146 along the axis 8014, rotate the viewing device 8200 aboutthe axis 8501, and cause the lens 8203 at the surgical site to movetransverse to the axis 8014 of the cannula 8010. This will expand thearea of the surgical site that the surgeon may view. When the adjustmentis complete, the surgeon may tighten the set screw 8148 and re-securethe viewing device 8200 to the second support 8140 of the supportapparatus 8110.

The method of securing two vertebrae 8601, 8602 together according toone embodiment may include the insertion of a vertebral fixationassembly 8620 through the cannula 8010 and attachment of the vertebralfixation assembly 8620 to two vertebrae (such as the L4 and L5vertebrae), as viewed in FIGS. 174-179. The fixation assembly 8620 maybe of any suitable construction and is shown in FIG. 176 as includingfour identical attachment devices 8622. Each attachment device 8622includes a threaded fastener 8624 or pedicle screw, placed in a vertebra8601 or 8602, as viewed in FIGS. 175 and 178. The fastener 8624 has afirst threaded portion 8626 with a first threaded diameter that threadsinto the vertebrae 8601, 8602 by screwing the fastener 8624 into thevertebrae. The fastener 8624 further includes a second threaded portion8628 with a second threaded diameter that may be less than the firstthreaded diameter. The second threaded portion 8628 extends away fromthe vertebrae 8601, 8602.

A first hexagonal engagement surface 8630, intermediate the first andsecond threaded portions 8626, 8628, allows gripping of the fastener8624 when the fastener is screwed into the vertebrae 8601, 8602. A firstconvex engagement surface 8632, adjacent the first hexagonal engagementsurface 8630 and the second threaded portion 8628, projects away fromthe vertebrae 8601, 8602. A second hexagonal engagement surface 8634projects away from the second threaded portion 8628 and allows furthergripping of the fastener 8624.

Each attachment device 8622 further includes a first fixation washer8640 (FIGS. 176 and 179) that engages the first convex engagementsurface 8632. The first fixation washer 8640 includes a first concaveengagement surface 8642 for abutting and slidingly engaging the firstconvex engagement surface 8632 of the fastener 8624.

The first fixation washer 8640 further includes spikes 8644, typicallythree, extending away from the vertebrae 8601, 8602. The spikes 8644 ofthe first fixation washer 8640 engage a lower knurled surface 8652 of avertebral fixation element 8650 that in FIGS. 174-176 is a spine plate.

An upper knurled surface 8654 of the fixation element 8650 engages thespikes 8664 of a second fixation washer 8660 that is identical to thefirst fixation washer 8640, but inverted, as viewed in FIGS. 176 and179. A second convex engagement surface 8672 of a threaded locking nut8670 abuts and slidingly engages the second concave engagement surface8662 of the second fixation washer 8660 when the locking nut 8670 isloosely threaded onto the second threaded portion 8628 of the fastener8624.

The convex and concave engagement surfaces 8632, 8642, 8662, 8672 allowangular adjustment of the fixation elements 8650, before the locking nut8670 is fully tightened, when the fasteners 8624 are not threaded intothe vertebrae 8601, 8602 exactly parallel to each other, as shownexaggerated in FIG. 175. These surfaces may typically allow for up to a12-degree offset of the axes of the two fasteners 8624.

One of two types of fixation elements 8650 may typically be used tosecure the vertebrae 8601, 8602 together. The first type may be a spinalplate 8651 (FIG. 176) with two slots 8653, 8655 extending along thelongitudinal axis 8657 of the spinal plate. The second threaded portion8628 of one fastener 8624, screwed into one vertebra 8601, extendsthrough one slot 8653 and the second threaded portion 8628 of anotherfastener 8624, screwed into another vertebra 8602, extends through theother larger slot 8655. Two of the spinal plates 8651, one on each sideof the vertebrae 8601, 8602, are used to secure the two vertebraetogether, as viewed in FIG. 174. The slots 8653, 8655 allow furthertransverse adjustment so that the same spinal plate 8651 may be used fordifferent size patients.

A second type of fixation element 8650 may be two universal side blocks8651 a (FIG. 179), each with one slot 8653 a extending along thelongitudinal axis 8657 a of each side block and a securement opening8655 a extending substantially perpendicularly to each slot 8653 a, asviewed in FIG. 179. The second threaded portion 8628 of a fastener 8624,screwed into one vertebra 8601, extends through one slot 8653 a and thesecond threaded portion 8628 of another fastener 8624, screwed intoanother vertebra 8602, extends through a slot 8653 a in an identicalside block 8651 a. The side blocks 8651 a further include lower andupper knurled surfaces 8652 a, 8654 a similar to the knurled surfaces8652, 8654 of the spinal plate 8651.

This second type of fixation element 8650 further includes a rod 8658 aextending from the opening 8655 a in one side block 8651 a to theopening 8655 a in the other side block 8651 a. Set screws 8659 a securethe rod 8658 a in each opening 8655 a when the rod 8658 a is positionedproperly to secure the vertebrae 8601, 8602 together, as viewed in FIG.177.

Four of the side blocks 8651 a, one on each side of each vertebra 8601,8602, and two rods 8658 a are used to secure the two vertebrae together.The slots 8653 a allow further transverse adjustment so that the sameside block 8651 a may be used for different size patients. The rods 8658a may also be cut to fit different sized patients.

The cannula 8010, support apparatus 8110, and vertebral fixationassembly 8620 described above may be used to perform an operation whichsecures two vertebrae 8601, 8602 together, such as the posterolateralfusion and screw placement described above. This type of operationtraditionally results in much blood loss because of the open access tothe spine required for its performance. Utilizing the cannula 8010 andsupport apparatus 8110 for placement of the fixation assembly 8620 atthe surgical site and attachment of the fixation assembly 8620 to thevertebrae 8601, 8602 in a manner to be described results in a much lessinvasive procedure and significantly less blood loss.

According to one embodiment, a method of fixing the vertebrae 8601, 8602of a patient together at two surgical sites includes two mainprocedures. In the first procedure, a first cannula 8010 is insertedinto the body 8130 of the patient adjacent one side of the spinalcolumn. A second cannula 8010 is inserted into the body 8130 of thepatient adjacent the other side of the spinal column. The second tubularportions 8040 of both cannulae are expanded as described above therebycreating a substantially complete view of both sides of the two adjacentvertebrae 8601, 8602. In one embodiment, the two adjacent vertebrae8601, 8602 are viewed by way of two endoscopes 8200 and one or moremonitors.

Alternatively, instead of using two cannulae and two endoscopessimultaneously so that both sides of adjacent vertebrae may be worked onby the surgeon at the same time, only one side of the adjacent vertebraemay be worked on and then the other side of the adjacent vertebrae maybe worked on. In this case, only one endoscope, one endoscope support8110, and one monitor is required. Two cannulae would most probably beused, one for each side of the vertebrae.

In the second procedure, the vertebrae 8601, 8602 are accessed throughthe cannulae 8010. Four insertion openings are drilled, one in each sideof each vertebra 8601, 8602, utilizing suitable instruments extendingthrough the cannulae 8010. The fasteners 8624 are inserted through eachcannula 8010 and are screwed one fastener 8624 into each insertionopening, thereby securing each fastener 8624 to a vertebra. The positionof the vertebrae 8601, 8602 are checked to ensure that the vertebraehave maintained the proper position. If necessary, the vertebrae 8601,8602 are repositioned. Eight fixation washers 8640, 8660, four lockingnuts 8670, and two fixation elements 8650 are moved through the cannulae8010. Four fixation washers 8640 and the fixation elements 8650 areplaced on the fasteners 8624. Each fastener 8624 is extended through onefixation washer and one slot in each fixation element 8650. Theadditional fixation washers 8660 are placed on the fasteners 8624. Thelocking nuts 8670 are threaded onto each fastener 8624 thereby fixingthe fixation elements 8650 to the vertebrae 8601, 8602 and securing thevertebrae together in a natural and permanent position within the body.Also, bone graft may be moved through the cannulae 8010 and placed inand around the fixation element 8650 and fasteners 8624 to permit aposterior fusion across the bony elements of the vertebrae 8601, 8602.

If necessary, the disc between the vertebrae 8601, 8602 may be removedthrough the cannula; the area between the vertebrae cleaned and thevertebrae prepared for receiving a fusion cage or cages and/or discreplacement material. This would be done before inserting the fasteners8624 or attaching the fixation elements 8650. The method may alsoinclude inserting, through the cannulae 8010, one or more appropriatelysized fusion cages and positioning the fusion cage(s) appropriatelyrelative to the vertebrae 8601, 8602; and inserting bone graft tissuethrough the cannulae 8010 and positioning the tissue in and around thefusion cage(s).

The fusion cage may be of any known construction. One typical fusioncage is a hollow rectangular cage that is inserted into grooves that areformed in facing bone surfaces of the vertebrae. Another type of fusioncage is a hollow cylindrical threaded cage which screws into positionbetween the vertebrae. Any suitable fusion cage may be used.

The cannulae 8010 and the shrink wrap 8102 are then removed from thebody and the incisions are suitably closed. After a time, vertebrae8601, 8602 and bone graft will grow together across the fusion cage(s)and in and around the fixation elements 8650. The vertebrae 8601, 8602will then no longer require the fixation assembly to maintain theirposition. The fixation elements 8650 and fasteners 8624 may then beremoved. The removal procedure may utilize the same type of apparatus aswas used in the first and second procedures (i.e., cannula, supportapparatus, etc.).

The first and second cannulae 8010 may be shifted slightly in theincisions in the body 8130 to desired locations within the incisions atany time during the first and second procedures or the removalprocedure. This is accomplished by changing the position of the supportapparatus 8110 by manipulating the arm 8301.

The method described above may, and most probably does, involve removalof tissue from the surgical site through the cannula 8010. Muscle, fat,and bone may be removed through the cannula 8010 to provide a properview of the vertebrae 8601, 8602 at the location to receive the fixationassembly 8620. Different tools may be used in the process of removingtissue. These tools may include a burr and/or tissue cutting blades thatare inserted through the cannula 8010.

A preferred tissue cutting blade device 8710 is shown in FIGS. 180-181.The device 8710 has an axis 8712 and includes inner and outer cuttingtubes 8740, 8750. Each of the inner and outer tubes 8740, 8750 hasopenings 8741, 8751 into their interiors. Cutting teeth 8745, 8755 arelocated on opposite sides of each opening 8741, 8751.

The inner tube 8740 rotates about the axis 8712 relative to the outertube 8750 within the outer tube. The inner tube 8740 rotates in oppositedirections a predetermined amount equal to one or more revolutions aboutthe axis 8712, and then rotates in the opposite direction the samepredetermined amount. Thus, the inner tube 8740 oscillates about theaxis 8712. As the inner tube 8740 oscillates/rotates about the axis8712, the cutting teeth 8745, 8755 on the inner and outer tubes 8740,8750 cut tissue. Alternatively, the inner tube 8740 may rotate in onedirection (clockwise or counterclockwise) within the outer tube.

During the cutting of tissue, a saline solution or the like may beforced through the annular space 8770 between the inner tube 8740 andthe outer tube 8750 to the surgical site. Suction may be applied in theopening 8741 of the inner tube 8740 to remove the cut tissue and thesaline solution from the surgical site.

A tubular sheath 8760 receives the inner and outer cutting tubes 8740,8750. The sheath 8760 extends along the length of the cutting tubes8740, 8750 and adjacent a distal end of the cutting tubes where thecutting teeth 8745, 8755 are located. The sheath 8760 is a stainlesssteel tube that is electrically insulated along its length from thepatient's body and from the outer tube 8750. An electrical insulator8763, such as a suitable polymer coating, is provided over the outsideand inside surfaces of the sheath 8760. However, a selected area 8762 ofthe outside surface of the sheath 8760 adjacent the distal end of thecutting tubes 8740, 8750 is not coated with the insulator 8763. Aportion 8765 of the distal end of the sheath 8760 is cut away so thatthe cutting teeth 8745, 8755 on the cutting tubes 8740, 8750 are notblocked by the sheath 8760 from cutting tissue.

An electric current from a current source 8766 is applied to the sheath8760. The electric current flows through the sheath 8760 and to theselected uncoated area 8762 of the sheath. The current then flowsthrough tissue and blood into the distal end of the outer cutting tube8750 and back to the current source through the outer cutting tube toform a completed circuit.

The current flow through the electrically energized sheath 8760 andouter cutting tube 8750 serves to electrocoagulate blood in the cuttingarea at the surgical site. Electrocoagulation of blood is known and anyother suitable electrocoagulation device may alternatively be used.

It is contemplated that viewing of the surgical site may be performedwithout using an endoscope. A microscope or glasses that magnify thesite may be used. In fact, any suitable viewing device may be used.Also, the procedure discussed above mentions drilling the vertebrae. Anysuitable alternative to drilling may be used such as using an awl orother instrument to form an opening to receive a fastener.

FIGS. 182-284 show other embodiments of surgical assemblies, accessdevices, viewing assemblies, and mounting assemblies. FIGS. 182-243 inparticular illustrate additional embodiments of access devices. FIGS.182-243 show access devices that are similar to the other access devicesdescribed herein, except as set forth below. FIGS. 244-284 showadditional embodiments of viewing elements and mounting systems foraccess devices. FIGS. 244-284 show viewing elements and mounting systemsthat are similar to the other viewing elements and mounting systemsdescribed herein, except as set forth below.

FIG. 182 shows a surgical assembly 9000 that includes an access assembly9002 and a viewing assembly 9004. The access assembly 9002 preferablyincludes an access device 9006 or retractor that is adjustably coupledwith an access device mounting fixture 9008. In various embodimentsdescribed herein, the access device 9006 is an elongate body having adistal portion 9010 and a proximal portion 9012 defining a passage 9014therethrough. Some embodiments of the adjustable coupling of the accessdevice 9006 and the access device mounting fixture 9008 are discussedherein.

The viewing assembly 9004 preferably includes a viewing element 9016coupled with a viewing element mounting fixture 9018. The viewingelement mounting fixture 9018 preferably is adjustably coupled with theaccess device mounting fixture 9008. Some embodiments of the adjustablecoupling of the viewing element mounting fixture 9018 and the accessdevice mounting fixture 9008 are described herein.

Access devices can have any number of configurations. In someembodiments, access devices have expanding proximal portions and/orexpanding distal portions. Expanding access devices can includedifferent configurations and structures, for example, access devices canincorporate overlapping leaves, overlapping skirt portions, overlappingtubes, sleeve portions, doughnut shaped portions, umbrella shapedportions, weaved portions, pop-up loops or springs, conical springs, andtelescoping arrangements, and other structures.

FIG. 183 is a schematic diagram illustrating possible expansiondirections for an access device 9020. In the illustrated embodiment, theaccess device 9020 has a generally oval-shaped cross-section. The accessdevice 9020 has a proximal portion 9022 and a distal portion 9024. Insome embodiments, the access device 9022 can be expanded in thelongitudinal direction 9026 increasing the overall length of the accessdevice 9020. In some embodiments, the proximal portion 9022 can beexpanded in a horizontal or transverse direction 9028. The distalportion 9024 of the access device 9020 in some embodiments can beexpanded in the direction 9030 of the minor access and/or in thedirection 9032 of the major access.

FIGS. 184-185 show distal portions of two access device embodiments andillustrate various overlapping arrangements. In some embodiments, askirt portion 9042 at a distal part of the access device 9040 isoverlapped relative another skirt portion 9044. The skirt portions 9042,9044 in the expanded configuration can have a generally oblong shapedcross-section. In the illustrated embodiment, the skirt portions 9042,9044 form a generally oval shaped cross-section. In the low profileconfiguration, the skirt portions 9042, 9044 generally can be overlappedin any suitable manner. In one embodiment, the skirt portions 9042, 9044can be overlapped so that when expanded, the skirt portions 9042, 9044at least partially overlap near a major access 9046 of the oval-shapedcross-section, as shown in FIG. 184. In another embodiment, the skirtportions 9042, 9044 can be overlapped so that when expanded, the skirtportions 9042, 9044 are positioned along a minor access 9048 of the ovalshaped cross section, as shown in FIG. 185. FIGS. 184-185 alsoillustrate that in some embodiments, an access device is configured toexpand by applying a force 9050 primarily along the minor axis 9048 orby applying a force 9052 primarily along the major axis 9046.

FIG. 186 is a schematic view of another embodiment of an expandableaccess device 9060 having an expansion mechanism 9062. In someembodiments, it is desirable to expand the access device 9060 using theexpansion mechanism 9062 positioned generally outside a passage 9064defined within the access device 9060. In other embodiments, theexpansion mechanism 9062 can be positioned within the passage 9064 ofthe access device 9060. In the illustrated embodiment, a push/pull rod9068 is coupled with a proximal portion 9070 of the access device 9060and to a distal portion 9072 of the access device 9060 to selectivelyexpand a distal skirt portion 9074. In some embodiments, the proximalportion 9070 comprises a collar portion 9076. In some embodiments, boththe proximal collar portion 9076 and the distal skirt portion 9074 canbe expanded simultaneously. Movement of a support mount or viewingelement mount 9078, in some embodiments, can trigger expansion and/orrotation of portions of the access device 9060.

Some access devices having expanding proximal portions are now describedin more detail. FIG. 187 is a plan view of one embodiment of an accessdevice 9080 that includes an expandable proximal portion 9082, shown ina flat pattern detail, and a distal portion 9084, a portion of which isshown schematically. The schematic representation of the distal portion9084 signifies that the proximal portion 9082 can be combined with anydistal portion disclosed or incorporated by reference herein, or anyother suitable distal portion. Preferably, the proximal portion 9082,when in the flat state, as illustrated in FIG. 187, has a generallyrectangular shape defined by a distal edge 9086, a proximal edge 9088, afirst longitudinal edge 9090, and a second longitudinal edge 9092. Thedistal edge 9086 of the proximal portion 9082 is located at or adjacentto the distal portion 9084. The proximal edge 9088 of the proximalportion 9082 is located at or adjacent the proximal end of the accessdevice 9080. The flat pattern view of the proximal portion 9082 suggestsmany suitable manufacturing processes. For example, the proximal portion9082 can be stamped out of sheet metal of a suitable thickness, orformed in any other suitable manner.

The proximal portion 9082 also includes at least one pair of flexfingers 9094, 9096. The pair of flex fingers 9094, 9096 preferablyincludes a latch finger 9094 located on the first longitudinal edge 9090and a catch finger 9696 located on the second longitudinal edge 9092. Inthe illustrated embodiment, four pairs of flex fingers are provided. Anysuitable number of flex fingers could be provided.

The catch finger 9096 and the latch finger 9094 preferably are elongatemembers that are configured to overlap, as discussed more fully below,such that the catch finger 9096 engages the latch finger 9094. When theflex fingers overlap to engage in this manner, the flex fingers are saidto be “interdigitated.” Whether there are one, two, three, four or morepairs of flex fingers, the flex fingers may be said to be interdigitatedwhen they overlap and engage each other in this manner. As discussedmore fully below, the flex fingers preferably are configured so thatwhen the flex fingers are interdigitated, the proximal portion 9082 canbe suitably sized for a wide variety of surgical procedures. Thisarrangement of interdigitated flex fingers is one form of an expansionmeans for the proximal portion 9082.

In one embodiment, the catch and latch fingers 9096, 9094 preferably arelocated at the same position longitudinally (i.e., at the same positionalong a line extending from the distal edge 9086 to the proximal edge9088), but on opposite sides of the proximal portion 9082. One of thecatch and latch fingers 9096, 9094 preferably has one or a series ofdetent holes 9098 formed therein. In the illustrated embodiment, thecatch finger 9096 is provided with six latch holes or detent holes 9098,as shown in FIG. 187, while the latch finger 9094 is provided with adetent hook feature 9100. In another embodiment, the catch finger 9096could be in the position of the latch finger 9094 in FIG. 187 and thelatch finger 9094 could be in the position of the catch finger 9096 inFIG. 187. FIG. 188 shows the proximal portion 9082 of the access device9080 in an overlapping configuration.

The detent holes 9098 preferably extend entirely through the thicknessof the catch finger 9096, but could extend only partially therethrough.The detent holes 9098 also could be formed as depressions, rather thenas holes in the catch finger 9096. In one embodiment, the detent hookfeature 9100 comprises a spherical surface that protrudes from at leastone side of the latch finger 9094. The detent holes 9098 and the detenthook feature 9100 are configured to engage each other in a secure mannerso that they will not become disengaged inadvertently. Although only asingle detent hook feature 9100 is located on the latch finger 9094,more could be provided so that when the flex fingers are engaged atleast two detent hook features 9100 may engage at least two detent holes9098. Such an arrangement may further decrease the likelihood of thecatch and latch fingers 9096, 9094 inadvertently becoming disengaged.One skilled in the art should recognize that other suitable detentarrangements could be employed.

As discussed above, the proximal portion 9082 of the access device 9080is expandable. In the embodiment illustrated by FIGS. 187-188, thedetent arrangement, and in particular, the detent holes 9098 provide arange discrete positions to which the proximal portion 9082 can beexpanded. Each of the six detent holes 9098 provides a position at whichthe detent hook feature 9100 of the latch member 9094 may engage thecatch member 9096. The transverse cross-sectional size of the proximalportion 9082 may be expanded by indexing the detent hook feature 9100from a detent hole 9098 farther from the second longitudinal edge 9092to a detent hole nearer to the second longitudinal edge 9092.

Expansion of the proximal portion 9082 of the access device 9080 may beaccomplished in any suitable manner. For example, an expander tool canbe used to expand the proximal portion 9082 by indexing the detent hookfeature 9100 from one detent hole 9098 to another. If the proximalportion 9082 is in its smallest configuration, e.g., the detent hookfeature 9100 is located in the detent hole 9098 farthest from the secondlongitudinal edge 9092, an expander tool can be inserted into theproximal portion 9082 and can be partially expanded until the expandertool engages opposites sides of the inner surface of the proximalportion 9082. Further expansion of the expander tool can be applied tothe opposite sides of the inner surface of the proximal portion untilthe force at the detent hook feature 9100 and the detent holes 9098exceeds the force resisting the inadvertent disengagement of the detent.When such force is applied, the detent will become disengaged and thedetent hook feature 9100 will disengage the detent hole 9098 in which itresides and the flex fingers will translate with respect to each otheruntil the detent hook feature 9100 comes to rest in a subsequent detenthole. One example of an expander tool is shown in FIG. 220.

The transverse cross-sectional size of the proximal portion 9082 may bereduced in any suitable manner. In one approach, the detent hook feature9100 is caused to disengage from the detent hole 9098 in which itresides and is subsequently indexed from a detent hole 9098 nearer tothe second longitudinal edge 9092 to a detent hole 9098 farther from thesecond longitudinal edge 9092. As in expansion, the detent hook feature9100 may become disengaged from the detent hole 9098 by the applicationof a force on the proximal portion 9082. For example, a compressiveforce could be applied to opposite outer surfaces of the proximalportion 9082.

Another manner of expanding or reducing the cross-sectional size of theproximal portion 9082 is illustrated in FIG. 189. The proximal portion9082 is illustrated in FIG. 189 in a reduced cross-sectional sizeconfiguration. An unlocking member 9102 is configured to be insertablebetween the interdigitated flex fingers 9104. In one embodiment, thethickness of the unlocking member 9102 increases toward the proximaledge thereof (e.g., the edge farthest from the distal edge of theproximal portion 9082). As the unlocking member 9102 is advanced betweenthe interdigitated flex fingers 9104, the flex fingers 9104 areseparated progressively decreasing the degree of engagement of thedetent hook feature 9100 and the detent hole 9098 in which it isinserted. An arrow A indicates the advancement of the unlocking member9102 with respect to the interdigitated flex fingers 9104 to disengagethe detent hook feature 9100 from the detent holes 9098.

FIG. 190 is a perspective view of one embodiment of an access assembly9120. The access assembly 9120 includes an access device 9122 thatincludes a proximal portion 9124. The access assembly 9120 also includesa skin wrap 9126 that at least partially surrounds the proximal portion9124. The proximal portion 9124 preferably includes a firstlongitudinally extending side 9128 and a second longitudinally extendingside 9130 that adjustably overlap. The first longitudinally extendingside 9128 preferably has a notch 9132 located on a major axis 9136 ofthe proximal portion 9124. The second longitudinally extending side 9130preferably has a notch 9134 located on a major axis 9136 of the proximalportion. The notches 9132, 9134, preferably are located on the samemajor axis 9136. The notches 9132, 9134 may be used to identify one ormore features on the access device 9122 or to couple the access device9122 to a mounting fixture or other structure.

The skin wrap 9126 prevents inadvertent expansion of the proximalportion 9124 of the access device 9122. The skin wrap 9126 preferably isremovable from the proximal portion 9124 when the proximal portion 9124is to be expanded. In one embodiment, the skin wrap 9126 is aheat-shrunk plastic sleeve that completely surrounds a portion of theproximal portion 9124.

In one arrangement, a release device is coupled with the skin wrap 9126,e.g., between the skin wrap 9126 and the proximal portion 9124, and iscapable of disengaging the skin wrap 9126 from the proximal portion 9124to allow the proximal portion 9124 to expand. One form of the releasedevice is a length of string.

After the proximal portion 9124 of the access device 9122 is released,the proximal portion 9124 may be expanded. An arrow B indicates motionof the proximal portion 9124, e.g., of the first longitudinal extendingside 9128 with respect to the second longitudinally extending side 9130,that expands the cross-sectional size of the proximal portion 9124. Thismotion may be provided by the expander tool illustrated in FIG. 220, inthe mounting fixture illustrated in FIGS. 267-270, or by any othersuitable means. The access device 9120 may be closed by way of theopposite motion.

FIG. 191 illustrates a proximal portion of an access device 9140. Theaccess device 9140 has an expandable proximal portion 9142. The proximalportion 9142 is covered by, or wrapped in, a stretchable member 9144.The terms “stretchable member,” as used herein, are broad terms, and caninclude elastic members, coatings, films, meshes, or other materials,and can also include other resilient, deformable, pliable, ductileand/or expandable materials. In some embodiments, the stretchable member9144 can be a polymer forming an outer coating about the proximalportion 9142 of the access device 9140. The proximal portion 9142 of theaccess device 9140 has inner and outer clamshells 9146, 9148 that can bemoved apart or together to expand or contract the cross-sectional areaof the proximal portion 9142. As the proximal portion 9142 expands, thestretchable member 9144 expands along with the inner and outerclamshells 9146, 9148 to maintain a relatively continuous outer surfaceabout the proximal portion 9142 of the access device 9140. Maintaining arelatively continuous outer surface along the proximal portion 9142reduces the likelihood that tissue will encroach into the surgical spaceformed by a passage of the access device 9140.

FIG. 192 is a perspective view of a proximal end 9164 of a proximalportion 9162 of one embodiment of an access device 9160. In theillustrated embodiment, the proximal portion 9162 of the access device9160 is expandable. The access device 9160 preferably has a plurality ofnotches 9166 formed along an upper surface or edge 9168 of the proximalportion 9162. When the proximal portion 9162 is expanded, the notches9166 preferably can be aligned. A locking ring 9170 or support mount canbe positioned over the expanded proximal portion 9162. The locking ring9170 has one or more pins 9172 or tabs that can be configured to engagethe notches 9166 at the proximal end 9164 of the access device 9160. Thelocking ring 9170 preferably maintains the proximal portion 9162 in theexpanded configuration when applied at the proximal portion 9162. Thelocking ring 9170 has an opening 9174 to provide access to a passage9176 of the access device 9160 and to a surgical location. In someembodiments, the locking ring 9170 can be formed as, or coupled with, anaccess device mounting fixture.

FIG. 193 is a perspective proximal end view of an access device 9180having a pivot rivet. FIG. 193 illustrates another embodiment of anaccess device 9180 having an expandable proximal portion 9182. Theaccess device 9180 has overlapping proximal segments. A first proximalsegment 9184 is positioned generally within a second proximal segment9186 such that the second proximal segment 9186 wraps around the firstproximal segment 9184. In other embodiments, the proximal segments 9184,9186 can be positioned in any suitable manner. As shown in theillustrated embodiment, slots 9188 are formed in one or more of theoverlapping proximal segments 9184, 9186. Pins or rivets 9190 can beplaced through the overlapping segments 9184, 9186 and into the slots9188 to facilitate expansion or contraction of the proximal portion9182. With reference to FIG. 193, the distal portion 9192 of the accessdevice 9180 can have one or more slots 9194 formed in one or more skirtportions 9196 where the distal portion 9192 is coupled with the proximalportion 9182. A pivot rivet 9198 can be placed within the slots 9194 inthe distal portion 9192 to couple the distal portion 9192 with theproximal portion 9182. The pivot rivet 9198 facilitates expansion of thedistal portion 9192 of the access device 9180 in connection with theexpansion of the proximal portion 9182. The pivot rivet 9198 and slot9194 arrangement advantageously provides for smooth translation betweenexpanded and contracted configurations and reduces the risk for bindingof the distal portions 9192 of the access device 9180.

With reference to FIGS. 194-195, a proximal portion 9202 of oneembodiment of an access device 9200 has a ratchet arrangement 9204and/or an expansion lock. A surface 9206 of the proximal portion 9202can be provided with one or a plurality of ridges, serrations, ornotches 9208. An overlapping end 9210 of the proximal portion 9202 canbe provided with a locking edge or ratchet mechanism 9212 to engage theridges, serrations, or notches 9208 along the surface 9206 of theproximal portion 9202. The proximal portion 9202 can be expanded orcontracted by moving the locking edge 9212 over the notched surface9206. The amount of expansion can be adjusted as desired using theratcheting and locking features.

FIG. 196 is a perspective view of another embodiment of an access device9220 that includes a proximal portion 9222 and a distal portion 9224. Asdiscussed more fully below, the proximal portion 9222 and the distalportion 9224 preferably are both expandable. The proximal portion 9222includes a first longitudinally extending side 9226 and a secondlongitudinally extending side 9228 that adjustably overlap. The firstlongitudinally extending side 9226 preferably has a generally U-shapedconfiguration that extends from a first lateral side 9230, around afirst longitudinal end 9232, to a second lateral side 9234 of the accessdevice 9220. The second longitudinally extending side 9228 preferablyhas a generally U-shaped configuration that extends from the firstlateral side 9230, around a second longitudinal end 9236, to the secondlateral side 9234 of the access device 9220.

In one embodiment, the first longitudinally extending side 9226adjustably receives a portion of the second longitudinally extendingside 9228. For example, the open end of the “U” of the firstlongitudinally extending side 9226 is somewhat wider than the open endof the “U” of the second longitudinally extending side 9228 such thatthe open end of the “U” of the second longitudinally extending side 9228can be received with the open end of the “U” of the first longitudinallyextending side 9226. In one embodiment, the first and secondlongitudinally extending sides 9226, 9228 are adjustably engaged by wayof a first pin-in-slot arrangement 9238. One form of the firstpin-in-slot arrangement 9238 provides corresponding control slots 9240,9242 on each of the first and second longitudinally extending sides9226, 9228 on each of the first and second lateral sides 9232, 9234 ofthe access device 9220. A pin 9246 extends at least partially throughboth of the slots 9240, 9242 so that the first and second longitudinallyextending sides 9226, 9228 are joined together. A second pin-in-slotarrangement 9238 similar to the pin-in-slot arrangement 9238 preferablyis provided on the second lateral side 9234 of the access device 9220.

In one embodiment, the adjustable engagement of the first and secondlongitudinally extending sides 9226, 9228 also includes a ratchetarrangement 9248 wherein corresponding rows of ratchet teeth areprovided on an overlapping portion of the first and secondlongitudinally extending sides 9226, 9228. The ratchet arrangement 9248enables discrete adjustment and expansion of the proximal portion 9222and also provides a means to lock the access device 9220 in place withany desired degree of expansion.

The proximal portion 9222 and the distal portion 9224 may also becoupled in any suitable manner. For example, the proximal portion 9222and the distal portion 9224 may be coupled by one or more pin-in-slotarrangements. In one embodiment, a third pin-in-slot arrangement 9250, afourth pin-in-slot arrangement 9252, and a fifth pin-in-slot arrangement9254 join the distal portion 9224 with the proximal portion 9222. Thethird pin-in-slot arrangement 9250 joins a second longitudinallyextending side 9256 of the distal portion 9224 to the secondlongitudinally extending side 9228 of the proximal portion 9222 at thesecond longitudinal end 9236 of the access device 9220. The thirdpin-and-slot arrangement 9250 can take any suitable form, but preferablyis similar to the first pin-in-slot arrangement 9240. A sixthpin-in-slot arrangement similar to the third pin-in-slot arrangement9250 preferably is provided on the first longitudinal end 9232 of theside of the access device 9220.

The fourth pin-in-slot arrangement 9252 joins a second longitudinallyextending side 9256 of the distal portion 9224 to the secondlongitudinally extending side 9228 of the proximal portion 9222 at thefirst lateral side 9230 of the access device 9220. The fourthpin-and-slot arrangement 9252 can take any suitable form, but preferablyis similar to the first pin-in-slot arrangement 9240, except as setforth below. The fourth pin-and-slot arrangement 9252 preferablyincludes an arcuate control slot formed in at least one of the secondlongitudinally extending side 9256 of the distal portion 9224 and in thesecond longitudinally extending side 9228 of the proximal portion 9222.A seventh pin-in-slot arrangement substantially similar to the fourthpin-in-slot arrangement 9252 preferably is provided on the secondlateral side 9234 of the access device 9220.

The fifth pin-in-slot arrangement 9254 joins a first longitudinallyextending side 9258 of the distal portion 9224 to the firstlongitudinally extending side 9226 of the proximal portion 9222 at thefirst lateral side 9230 of the access device 9220. The fifthpin-and-slot arrangement 9254 can take any suitable form, but preferablyis similar to the first pin-in-slot arrangement 9240, except as setforth below. The fifth pin-and-slot arrangement 9254 preferably includesan arcuate control slot formed in at least one of the firstlongitudinally extending side 9258 of the distal portion 9224 and in thefirst longitudinally extending side 9226 of the proximal portion 9222.In the illustrated embodiment, the fourth and fifth pin-in-slotarrangements 9252, 9254 share at least one slot. An eighth pin-in-slotarrangement substantially similar to the fifth pin-in-slot arrangement9254 preferably is provided on the second lateral side 9234 of theaccess device 9220.

The access device 9220 also provides a first actuator 9260 and a secondactuator 9262. The first and second actuators 9260, 9262 preferably arein the form of rods that extend proximally of the proximal portion 9222.The first actuator 9260 may extend from the first longitudinallyextending side 9226 of the proximal portion 9222 or of the firstlongitudinally extending side 9258 of the distal portion 9224 (e.g., asa discrete or an integral component thereof). The second actuator 9262may extend from the second longitudinally extending side 9228 of theproximal portion 9222 or of the second longitudinally extending side9256 of the distal portion 9224 (e.g., as a discrete or an integralcomponent thereof). The first and second actuators 9260, 9262 can behandled by a medical practitioner to expand the access device 9220,e.g., by applying a force thereon to impart movement in a directionindicated by arrows H.

FIG. 197 shows contraction of the access device 9220, e.g., to configurethe access device 9220 for insertion or withdrawal from the body.Movement of the access device 9220 from the expanded configuration tothe un-expanded configuration is indicated by arrows I. FIG. 198 showsexpansion of the access device 9220, e.g. to provide a working space fora surgical procedure. As in FIG. 196, movement is indicated by thearrows H.

Embodiments featuring various methods and structures for achievingdistal expansion are described in further detail below. With referenceto FIGS. 199-201, one embodiment of an access device 9280 has anexpandable distal portion 9282 with anchor portions 9284 to fix theextent of the expansion of the distal portion 9282. The access device9280 is configured to be expanded without the use of an expansion tool.The access device 9280 has a proximal collar portion 9286 coupled with adistal portion 9282 having right and left skirt halves 9288, 9290. Thedistal portion 9282 is coupled with the proximal portion 9286 at a pivotlocation 9292. The left and right skirt halves 9288, 9290 compriseanchor portions 9284. In some embodiments, the anchor portions 9284 cancomprise a plurality of teeth. In the illustrated embodiment, the accessdevice 9280 has a low profile configuration for insertion. In the lowprofile configuration, the skirt portions 9288, 9290 can be wrapped inan overlapping configuration. Upon insertion, the anchor portions 9284are configured to be positioned in a fixed location. The access device9280 is expanded from the low profile configuration to an expandedconfiguration by rotating the proximal portion 9286 of the access device9280. In the illustrated embodiment, the access device 9280 is rotatedin a clockwise direction to achieve expansion. The anchor portions 9284preferably are held stationary while the access device 9280 is rotated.In some embodiments, the anchor portions 9284 can engage the tissue ofthe patient to maintain a stationary position. In some embodiments, alength 9294 of the distal portion 9282 in the expanded configuration isabout three times greater than a length 9296 of the distal portion 9282in the low profile configuration. To remove the access device 9280, theproximal portion 9286 is rotated in the opposite direction. In theillustrated embodiment, rotating the proximal portion 9286 in acounterclockwise direction returns the access device 9280 to the lowprofile configuration for removal.

FIGS. 202-203 illustrate one embodiment of an access device 9300 havingan inflatable portion. In the illustrated embodiment, the access device9300 incorporates a hoop skirt balloon system. In a deployedconfiguration, highly pressurized hoop balloons 9302 hold a skirtsection 9304 and a collar section 9306 open to provide access to asurgical location. Inflation ports 9308, 9310 can be provided for thecollar section 9306 and for the skirt section 9304. In one embodiment,the access device 9300 comprises an oval-shaped mounting ring 9312 neara proximal portion 9314 of the access device 9300. The hoop balloons9302 are sized so that when inflated, the cross sectional area at adistal portion 9316 of the access device 9300 is greater than thecross-sectional area at a proximal portion 9314 of the access device9300. The access device 9300 can be constructed with hoop balloons 9302connected with web material 9318 or any other suitable material. Wheninflated, the hoop balloons 9302 are relatively more rigid than the webmaterial 9318 connecting adjacent hoop balloons 9302. The flexibility ofthe compliant web material 9318 between the hoop balloons 9302 generallyallows the proximal portion 9314 of the access device 9300 to bemanipulated to provide better access and visualization of the surgicalarea. The flexibility of the hoop skirt balloon arrangement isadvantageous for reaching some anatomical structures. The access device9300 can be inflated by hand pump or by a pressure cartridge, such as,for example, a CO₂ cartridge. The access device 9300 can be deflatedusing a vacuum pump. In other embodiments, pressure can be released bysimply opening the inflation ports 9308, 9310.

With reference to FIG. 204, in one embodiment, a collapsible accessdevice 9320 comprises semicircular, semi-oblong, or a combination ofsemi-circular and semi-oblong bands 9322 interleaved together.Individual bands 9322 can pivot, or pivot and translate, along aninternal track 9324. The bands 9322 can be configured so that a proximalportion 9326 of the access device 9320 has cross-sectional area that isgenerally smaller than the cross-sectional area at a distal portion 9328of the access device 9320, in the expanded configuration. In the reducedprofile configuration, the semicircular bands 9322 can be positioned ina collapsible arrangement, each band 9322 fitting at least partiallywithin the next larger size band 9322. To deploy the access device 9320into the expanded configuration, one or more internal rods 9330 can beprovided in the internal track 9324 to push the bands 9322 toward theexpanded configuration.

With reference to FIGS. 205-206, one embodiment of an access device 9340includes a plurality of weaved bands 9342. The bands 9342 preferably arestainless steel bands; however, other materials can be used. The bands9342 are coupled with first and second end collars 9344, 9346 at theproximal and distal ends 9348, 9350 of the access device 9340. In oneembodiment, the end collars 9344, 9346 preferably are formed of anelastomeric overmold. In other embodiments any suitable material can beused. In the access device 9340 of the illustrated embodiment, thecross-sectional area of the access device 9340 can be increased orreduced without the use of an expanding tool. Pulling up on the proximalcollar 9344 reduces the cross-sectional area of the access device 9340for insertion. Pushing down on the proximal collar 9344 increases thecross-sectional area to provide increased access to the surgicallocation.

FIG. 207 is a cross-sectional view of one embodiment of an access device9360 having a generally spherical joint 9362 similar in function to aball joint located between a proximal 9364 and a distal portion 9366.The spherical joint 9362 includes in one embodiment a first sphericalsurface 9368 and a second spherical surface 9370 facing the firstspherical surface 9368. The surfaces 9368, 9370 are configured so thatthe proximal portion 9364 can be manipulated with respect to the distalportion 9366 in a multitude of directions to enhance access to andvisualization of a surgical location. In the illustrated embodiment, theproximal portion 9364 can be pivoted about multiple axes.

FIG. 208 is a schematic view of another embodiment of an inflatableaccess device 9380 that is shown applied across an incision in apatient's skin 9382. The access device 9380 has a positionablepassageway 9384. The access device 9380 preferably comprises a balloonskirt 9386 along a distal portion 9388 of the access device 9380. In theexpanded configuration, the balloon skirt 9386 is inflated and defines apassage 9390 that has a cross-sectional area at a distal location 9392that is greater than a cross-sectional area at a more proximal location9394. In some embodiments, the balloon portion 9386 can be positioned atleast partially outside the patient. For example, the balloon 9386 canextend above the skin incision 9382, in some embodiments. The balloon9386 has an inflation fill port 9396 in one embodiment. The accessdevice 9380 has collar portion 9398 that can be positioned inside anopening in the balloon skirt portion 9386. In one embodiment, the collar9398 is movable to various positions because of the flexibility of theballoon portion 9386. The proximal collar portion 9398 can be easilyrepositioned while in the opening of the balloon skirt 9386 to betteraccess a surgical location. In use, a dilator can be used to expand theincision 9382 in the patient's skin. The access device 9380, with theballoon 9386 deflated, is inserted into the patient. The balloon 9386 isinflated to retract tissue and provide an expanded surgical area. Insome embodiments, the collar 9398 can be inserted simultaneously withthe deflated balloon 9386. In some embodiments, the collar portion 9398can be inserted after inflation of the balloon skirt portion 9386. Theflexibility of the balloon skirt portion 9386 enables the collar 9398 tobe manipulated, angled, or rotated to achieve access and visualizationof the surgical location as desired.

With reference to FIG. 209, an access device 9400 has a proximal portion9402 with a generally oval-shaped cross-section, a distal portion 9404with right and left skirt portions 9406, 9408, and a plurality of leaves9410 positioned between the right and left skirt portions 9406, 9408. Inother embodiments, the proximal portion 9402 can have any other oblongshaped cross section. Three leaves 9410 are coupled with the proximalportion 9402 of the access device 9400 in one embodiment. A first leaf9412 is coupled with the left skirt portion 9408. A second leaf 9414 iscoupled with the right skirt portion 9406. The third leaf 9416 iscoupled with the first and second leaves 9412, 9414. The leaves 9410 cantranslate over each other and move from a contracted configuration to anexpanded configuration. The access device 9400 of the illustratedembodiment is particularly advantageous because the distal portion 9404,in the expanded configuration, can accommodate surgical proceduresacross up to four or more adjacent vertebrae. In one embodiment, thedistal portion 9404 of the access device 9400 can expand up to about 120mm.

With reference to FIG. 210, an access device 9420 has a generallyoval-shaped proximal portion 9422 and an expandable distal portion 9424.The expandable distal portion 9424 has left and right skirt portions9426, 9428. The left and right skirt portions 9426, 9428 are coupledwith the proximal portion 9422 with pins or rivets 9430. The distalportion 9424 comprises first and second slide members 9432, 9424 coupledwith the proximal portion 9422 on either side of the access device 9420.The slide members 9432, 9434 preferably comprise slot portions 9436. Thedistal portion 9424 of the access device 9420 comprises first and secondextension members 9438, 9440 on each side. In the illustratedembodiment, the first extension member 9438 is coupled with the leftskirt portion 9426 via a pin, or a rivet, or another suitable couplingmember 9442. The second extension member 9440 is coupled with the rightskirt portion 9428 via a pin, or a rivet, or another suitable couplingmember 9444. The first and second extension members 9438, 9444 arecoupled with the slot 9436 of the slide member 9432. In one embodiment,the slide member 9432 and the first and second extension members 9438,9440 form a linkage enabling the expansion of the distal portion 9424.The distal portion 9424 of the access device 9420 comprises a flexiblemesh 9446 extending between the slide member 9432 and the left and rightskirt portions 9438, 9440. The flexible mesh 9446 can comprise any typeof flexible material including stretchable materials, e.g., polymericmaterials, elastomeric materials, or metal mesh constructions. In theillustrated embodiment, the first and second extension members 9438,9440 are coupled with the slide member 9432 by a coupling member 9450 ata bottom portion of the slot 9436 in an expanded configuration. In oneembodiment, in the expanded configuration, the first and secondextension members 9438, 9440 act as a locking structure to maintain theskirt portion 9426, 9428 in the expanded configuration. In the expandedconfiguration, the flexible mesh 9446 preferably reduces the amount oftissue that can penetrate into a passage 9448 defined by the accessdevice 9420. To return the access device 9420 to the low profileconfiguration, the coupling member 9450 is raised in the slot 9436 sothat the left and right skirt portions 9426, 9428 are drawn together asthe extension members 9438, 9440 move toward the center of the accessdevice 9420. The access device 9420 of the illustrated embodiment isparticularly useful in surgical procedures involving multiple spinallevels.

With reference to FIG. 211, an access device 9460 has a proximal portion9462 and an expandable distal portion 9464. The proximal portion 9462can have a circular cross-section, an oval cross-section, or anotheroblong shaped cross-section. The distal portion 9464 of the accessdevice 9460 comprises a plurality of blades 9466. The blades 9466 arecoupled with an intermediate ring 9468. The intermediate ring 9468 iscoupled with the proximal portion 9462 of the access device 9460. Theproximal portion 9462 of the access device 9460 preferably can pivotwith respect to the intermediate ring 9468 and with respect to thedistal portion 9464 of the access device 9460. The blades 9466 can bepositioned in a collapsed configuration for insertion into a patient andcan be fanned out into an expanded configuration to provide space forperforming a surgical procedure. The blades 9466 preferably pivot withrespect to the intermediate ring 9468. The intermediate ring 9468enables the access device 9460 and the proximal and distal portions9462, 9464 to be positioned in or to have a plurality of pivotconfigurations.

FIGS. 212-213 illustrate another embodiment of access device 9480. Theaccess device 9480 has a proximal portion 9482 and a distal portion9484. The access device 9480 has an intermediate ring 9486 configured toexpand or contract the distal portion 9484 of the access device 9480. Inthe illustrated embodiment, the proximal portion 9482 has an oval-shapedcross-section. The distal portion 9484 of the access device 9480 hasleft and right skirt portions 9488, 9490. The distal portion 9484 of theaccess device 9480 also has first and second mesh leaves 9492, 9494coupled with the proximal portion 9482 of the access device 9480. In theillustrated embodiment, the mesh leaves 9492, 9494 include a mesh 9496and a frame member 9498. The frame member 9498 surrounds the mesh 9496.In one embodiment, the frame 9498 is configured to collapse along atleast one edge to enable the frame member 9498 to take on a low profileconfiguration. For example, one edge of the frame 9498 may have a gapformed therein. In some embodiments, e.g., where the frame member 9498is collapsible, the mesh 9496 is a stretchy member that can expand asthe access device 9480 is deployed. The frame member 9498, incombination with the mesh 9496, provides sufficient rigidity to preventtissue encroachment, to retract tissue, or to retract tissue and preventtissue encroachment. In some embodiments, movement of the intermediatering 9486 can actuate the expansion or contraction of the access device9480 at the distal portion 9484. With reference to FIGS. 212-213, movingthe intermediate ring 9486 proximally acts to contract the distalportion 9484 of the access device 9480. Moving the intermediate ring9486 distally acts to expand the distal portion 9484 of the accessdevice 9480. The mesh 9496 material can be a metal weave, a polymericmaterial, or any other suitable material for preventing or minimizingthe intrusion of tissue into the surgical space.

With reference to FIGS. 214-215, an access device 9500 is providedhaving a proximal portion 9502 and an expandable distal portion 9504.The access device 9500 has an intermediate ring 9506 coupled with theproximal portion 9502 of the access device 9500 and also coupled withthe distal portion 9504 of the access device 9500. The intermediate ring9506 in some embodiments can be configured to actuate the expandabledistal portion 9504 from an expanded configuration to a contractedconfiguration. The distal portion 9504 of the access device 9500 in theillustrated embodiment comprises a plurality of wire loops 9508 coupledwith left and right skirt portions 9510, 9512 of the distal portion9504. The wire loop portions 9508 preferably act to limit tissueintrusion into a surgical space defined within the access device 9500.In the illustrated embodiment, movement of the intermediate ring 9506proximally acts to expand the distal portion 9504 of the access device9500. Moving the intermediate ring 9506 distally acts to contract thedistal portion 9504 of the access device 9500.

With reference to FIGS. 216-219, an access device 9520 has a proximalportion 9522 and an expandable distal portion 9524. The access device9520 preferably is configured to be expanded or contracted configurationby manipulating a proximal portion 9522 of the access device 9520. Thedistal portion 9524 has left and right skirt portions 9526, 9528. In theillustrated embodiment, the left and right skirt portions 9526, 9528 arecoupled with, or integrally formed with, proximal skirt extensions 9530.The proximal skirt extensions 9530 are configured to cooperate with acollar portion 9532 to form a proximal portion 9522 of the access device9520. The left and right skirt portions 9526, 9528 comprise holes orslots 9534 for receiving a coupling device 9536, such as a pin or arivet. The left and right skirt portions 9526, 9528 can pivot about thecoupling device 9536. In the illustrated embodiment, the collar portion9532 is coupled with the left and right skirt portions 9526, 9528 by therivet on first and second sides of the access device 9520. The left andright skirt portions 9526, 9528 can have flexed hinge points 9538 wherethe skirt portion is formed or coupled with the proximal skirtextensions 9530. The access device 9520 can be actuated from a closedposition to an open position by pulling up on the proximal skirtextension 9530 while pushing down on the proximal collar portion 9532.Pushing down on the proximal collar portion 9530 forces the skirtportions 9526, 9528 to pivot about the flexed hinge points 9538 androtate the skirt portions 9526, 9528 into the expanded configuration.The access device 9520 is returned to a closed position by pressing downon the proximal skirt extensions 9530 and pulling up on the proximalcollar portion 9532. Manufacturing an access device 9520 according tothe illustrated embodiment advantageously reduces the number of partsassociated with providing an access device 9520, thereby reducing theexpense and cost of production.

FIGS. 220-221 show one embodiment of an access device 9540 having aproximal portion 9542 and a distal portion 9544. An expander tool 9546,which may be used to increase the cross-sectional area of the distalportion 9544, is shown in FIG. 220 inserted into the access device 9540.

The distal portion 9544 includes a first longitudinally extending side9548 and a second longitudinally extending side 9550 with a tab-in-slotengagement arrangement. In one arrangement, a locking tab 9552 with alatch hook 9554 is provided on opposing sides of the secondlongitudinally extending side 9550 of the distal portion 9544 and acatch slot 9556 is provided on opposing sides of the firstlongitudinally extending side 9548 of the distal portion 9544. The catchslot 9556 is configured to receive the latch hook 9554 which causes thefirst and second longitudinally extending sides 9548, 9550 to beengaged, preventing transverse motion of the sides 9548, 9550 withrespect to each other. The catch slot 9556 and latch hook 9554 can bepositioned such that their engagement occurs when the distal portion9544 is expanded or to be engaged when the distal portion 9544 iscontracted. Thus, the tab-in-slot engagement arrangement may preventinadvertent expansion or inadvertent contraction of the distal portion9544. In another embodiment, a plurality of slots similar to the slot9556 can be provided to enable discrete expansion positions for thedistal portion 9544.

The latch hooks 9554 and the catch slots 9556 preferably are located onor near a minor axis of the distal portion 9544. This facilitatesexpansion of the distal portion 9544. For example, the expansion of thedistal portion 9544 may be achieved by first inserting the expander tool9546 into the distal portion 9544 through the proximal portion 9542. Theexpander tool 9546 may then be aligned with the latch hooks 9554 whichextend through the catch slots 9544 into an enclosed volume 9558 in thereduced cross-sectional size arrangement of the distal portion 9544,which volume 9558 is defined at least in part by the distal portion9544. The proximal end of the expander tool 9546 may then be actuated tocause the distal portion thereof to engage the latch hooks 9554. A pairof arrows C indicate actuation of the expander tool 9546 to engage thelatch hooks 9554. Further actuation of the expander tool 9546 causes thelatch hooks 9554 to be moved outside of the catch slots 9556 so that thefirst and second sides 9548, 9550 of the distal portion 9544 no longerengage each other.

The expander tool 9546 may then be rotated about 90 degrees so that thedistal portion thereof may engage a major axis of the distal portion9544. Expansion of the expander tool 9546 causes the distal portionthereof to engage an inner surface of the distal portion 9544. Furtherexpansion thereof causes the distal portion 9544 to be further expanded.Where the distal portion 9544 is provided with a plurality of catchslots 9556, the expansion along the major axis may index the distalportion 9544 to a selected discrete location. Where a single catch slot9556 is provided, the distal portion 9544 may be expanded to a discreteexpanded position. In this case, the latch hook 9554 will not be inengagement with a catch slot 9556 in the un-expanded configuration.Thus, the motion indicated by the arrows C will not be needed. Ofcourse, where desired, the distal portion 9544 could be expanded to anyposition between the un-expanded position and the position at which thelatch hook 9554 and the catch slot 9556 become engaged if suitableconditions exist to prevent the inadvertent contraction of the distalportion 9544.

In another embodiment, a distal portion is provided with a single catchslot and a single latch hook which is received by the catch slot in theun-expanded configuration. Expansion of this embodiment is similar tothe expansion described above except that after the latch hook isdisengaged from the catch slot, as discussed above, the distal portionmay be expanded to any of a range of positions.

In one embodiment, one or more rivets are provided to maintain flapcontact, e.g., on the proximal edge of the distal portion 9544.

In another embodiment, each of the sides is provided with one latch hookand one catch slot. In particular, FIG. 221 shows a portion of anotherembodiment of a distal portion that includes a first longitudinallyextending side 9548 a that includes a locking tab 9552 a with a latchhook 9554 a and a catch slot 9556 a. The catch slot 9556 a and the latchhook 9554 a are located across the first longitudinally extending side9548 a from one another. These structures are configured to engagecorresponding structures on a second longitudinally extending side (notshown). The expansion of the distal portion constructed from the firstlongitudinally extending side 9548 a and the corresponding secondlongitudinally extending side is expandable as discussed above inconnection with the distal portion 9544.

FIG. 222 is a cross-sectional view of a portion of an access device 9560with a deployment mechanism 9564. The access device 9560 includes aproximal portion 9568 and a distal portion 9572. Engagement of theproximal and distal portions 9568, 9572 is at least in part defined by apivot assembly 9576 that includes a pivot notch 9580 and a pivot finger9584, as shown in FIG. 224. The pivot assembly 9576 enables the distalportion 9572 and the proximal portion 9568 to pivot with respect to eachother.

The deployment mechanism 9564 preferably includes a pull strap 9588 anda plurality of catch hooks 9592. Preferably three catch hooks 9592 areprovided. The catch hooks 9592 are configured to engage a portion of theproximal portion 9568 of the access device 9560 when the deploymentmechanism is moved to a deployed position. The pull strap 9588 is anelongate member that has a distal end 9596 and a proximal end 9600.Preferably, a rivet 9604 (or other suitable fastener) is provided tocouple the distal end 9596 of the pull strap 9588 with the distalportion 9572 of the access device 9560. The proximal end 9600 of thepull strap 9588 preferably includes a pull feature, such as athrough-hole 9608, that provides a means to exert a force on the pullstrap 9588. Application of a force on the pull strap 9588 is illustratedby an arrow D in FIG. 222.

An arrow D illustrates motion that actuates the deployment mechanism9564 from the un-deployed configuration (FIG. 222) to the deployedconfiguration (FIG. 223) to deploy the access device 9560. In oneembodiment, the pull strap 9588 has a length sufficient to allow thehooks 9592 to extend proximal of the proximal end of the proximalportion 9568. Preferably the hooks 9592 are also configured to engagethe proximal end of the proximal portion 9568, as illustrated in FIG.223. The access device 9560 is thereby locked into the expanded stateillustrated in FIG. 223. The pivot assembly 9576 permits the distalportion 9572 of the access device 9560 to move with respect to theproximal portion 9568 when the force applied to the pull strap 9566 istransmitted to the distal portion 9572. In particular, the pivot finger9584 pivots in the pivot notch 9580 as the distal portion 9572 extendsoutwardly.

An arrow E in FIG. 223 illustrates further expansion of the accessdevice 9560. In particular, where further expansion of the distalportion 9572 is desired, an expander tool, such as the expander tool9556 of FIG. 220 may be inserted into the access device 9560. A forceurging greater expansion of the distal portion 9572, which isillustrated by the arrow E, may be applied by the expander tool 9556.Deployment may be assisted by the expander tool 9556 in this manner.

Movement of the deployment mechanism 9564 from the deployed positionback to the un-deployed position may be achieved by providing a forceand movement of the proximal end 9600 of the pull strap 9588 asindicated by an arrow F. This force and movement moves the catch hook9592 off of the proximal end of the proximal portion 9568. The pivotfinger 9584 is then free to pivot in the pivot notch 9580, allowing thedistal portion 9572 to move from the deployed position (FIG. 223) backto the un-deployed position (FIG. 222), or to a less deployed, but notfully un-deployed position.

FIG. 225 is a perspective view of another embodiment of an access device9620 having a proximal portion 9622, a distal portion 9624 that has afirst configuration for insertion and a second configuration after beinginserted and expanded, and a lock 9626. The second configuration isillustrated in FIG. 225. The access device 9620 is configured to belocked into at least the second configuration.

In the illustrated embodiment, the distal portion 9624 comprises a sheetportion 9628 that is an arcuate in shape if rolled flat. However, whencoupled with the proximal portion 9622 and in the second configuration,the sheet portion 9628 of the distal portion 9624 forms a frusto-conicalshape with an area of overlap 9632. The area of overlap 9632 is the areawhere a first edge 9636 of the sheet portion 9628 extends some distanceover a second edge 9640. A first area 9644 of the sheet portion 9628adjacent the first edge 9636 extends outside of a second area 9648 ofthe sheet portion 9628 adjacent the second edge 9640. Thus, the firstarea 9644 forms an outside surface while the second area forms an insidesurface of the distal portion 9624.

The lock 9626 can take many forms. FIG. 225-226 illustrate a J-hook lock9652. The J-hook lock 9652 includes a J-shaped lock tab 9656 and alocking slot 9660. The locking slot 9660 is formed in the sheet portion9628 at a location selected to provide sufficient expansion of thedistal portion 9624. The J-shaped lock tab 9656 is movable from a firstlocation outside the locking slot 9660 to a second location within thelocking slot 9660. In the first location, the J-shaped lock tab 9656extends from the first area 9644 (e.g., the outer surface) around thedistal end of the distal portion 9624 to the second area 9648 (e.g., theinner surface). See FIG. 226.

Movement of the J-shaped lock tab 9656 to the second location isindicated by an arrow G in FIG. 225. The J-shaped lock tab 9656 extendsfrom the first area 9644 (e.g., the outer surface), through the lockingslot 9660, and around the second edge 9640 when in the second position.In the second position, the J-shaped locking tab 9656 prevents movementof the second area 9648 with respect to first area 9644 to lock thedistal portion 9624 in the second configuration.

In the illustrated embodiment, the first and second areas 9644, 9648 aretwo ends of a single curled sheet. In another embodiment, the first andsecond areas 9644, 9648 may be overlapping portions of two differentcurled elongate sheets that generally extend along longitudinal axeslocated between the two sheets. Other embodiments of distal portions andother access devices can employ a lock similar to the lock 9626.

FIG. 227 is a partial distal-end view of an access device similar to theaccess device 9620 showing another embodiment of a lock 9626 a. The lock9626 a includes an area of overlap 9632 a. In the area of overlap 9632a, a first area 9644 a of a sheet portion 9628 a adjacent a first edge9636 a generally extends outside of a second area 9646 a of the sheetportion 9628 a adjacent a second edge 9640 a. An undulation 9660 isformed at a location selected to provide sufficient expansion of theaccess device with which the lock 9626 a is used. The undulationprovides a notch 9664 into which the first edge 9636 a rests in thesecond configuration. Inadvertent collapse of the access device withwhich the lock 9626 a is used is thereby prevented.

FIG. 228 is a partial distal-end view of an access device similar to theaccess device illustrated in FIG. 225, showing another embodiment of alock 9626 b. The lock 9626 b is formed at a first edge 9636 b and asecond edge 9640 b. The first and second edges 9636 b, 9640 b are formedwith one or more interlocking protrusions such that when the distalportion of the access device having the lock 9626 b is expanded adesired amount, the protrusion(s) on the first and second edge 9636 b,9640 b engage one another in a manner that prevents inadvertent collapseof the distal portion.

With reference to FIGS. 229-231, additional embodiments of accessdevices having locking elements are illustrated. In the firstembodiment, the access device 9670 has a proximal portion 9672 and adistal expandable portion 9674. The distal expandable portion has leftand right skirt components 9676, 9678. The left and right skirtcomponents 9676, 9678 are coupled with the proximal portion 9672 of theaccess device 9676 with a rivet 9680. The left and right skirtcomponents 9676, 9678 comprise slots 9682, 9684. A rivet 9686 is placedwithin the slots 9682, 9684 of the right and left skirt components 9676,9678. The left and right skirt components 9676, 9678 can be overlappedto slide relative one another from a contracted configuration to anexpanded configuration. At a distal portion 9674 of the access device9670, a spring tab 9688 is formed in the right skirt component 9678. Asthe distal portion 9674 of the access device 9670 is expanded, and theleft skirt portion 9676 moves relative the right skirt portion 9678, thespring tab 9688 is configured to pop out to hold the left skirtcomponent 9676 in the expanded configuration relative the right skirtcomponent 9678. The spring tab 9688 acts to lock the skirt in the openposition. The spring tab 9688 has an access hole so that the spring tab9688 can be manipulated with an instrument to unlock or disengage thetab hook prior to returning the access device 9670 to the reducedprofile configuration.

In another embodiment illustrated in FIGS. 230-231, an access device9690 has a proximal portion 9692 and a distal portion 9694. The distalportion 9694 has left and right skirt components 9696, 9698 coupled witha proximal portion 9692 of the access device 9690 via a rivet 9700. Theleft and right skirt components 9696, 9698 comprise slots 9702, 9704 anda rivet 9706 to couple the left and right skirt components 9696, 9698together. As the left and right skirt components 9696, 9698 areexpanded, the rivet 9700 travels along the slots 9702, 9704. A clip 9708is provided on one of the left and right skirt components 9696, 9698.The clip 9708 can be a piece of metal shaped in the form of a “J”. Inthe illustrated embodiment, the clip 9708 is coupled with the skirtcomponent 9696 using a rivet 9710, or other coupling mechanisms, toallow the clip 9708 to rotate relative to the skirt component 9696. Inthe illustrated embodiment, the J clip 9708 is coupled with the leftskirt component 9696. The right skirt component 9698 comprises a slot9712 for receiving the clip 9708 when the distal portion 9694 of theaccess device 9690 is in the fully expanded configuration. The clip 9708can be manipulated with a surgical instrument to hold open the distalportion 9694 of the access device 9690 in the expanded configuration.The tab 9714 on the end of the clip preferably is strong enough towithstand the forces placed on the distal portion 9694 of the accessdevice 9690.

FIGS. 232-234 illustrate one embodiment of a retractor 9720 or accessdevice that may advantageously be deployed to enable surgical proceduresto be performed minimally invasively. The retractor 9720 is similar tothose of FIGS. 191 and 210, except as set forth below. In addition, theretractor 9720 advantageously can be coupled with a viewing elementmount arrangement that enables expansion of the retractor, particularlyat the proximal end. An example of such an arrangement is discussedbelow in connection with FIG. 271 and in greater detail in U.S. patentapplication Ser. No. 10/845,389, filed May 13, 2004, bearing the titleACCESS DEVICE FOR MINIMALLY INVASIVE SURGERY.

FIGS. 232-234 show that the retractor 9720 includes an elongate body9722 and an expandable shroud 9724. The term “shroud” is used in itsordinary sense to mean something that covers, screens, or guards and isa broad term and it includes flexible and expandable structures that atleast partially cover, screen, or guard an access device, a retractor,an elongate body, a passage, a working space, or a surgical field. Theterm “shroud” includes structures that at least partially cover, screen,or guard a passage, a working space, or a surgical field fromencroachment of tissue displaced by an access device, a retractor, or anelongate body when applied to a patient. As discussed more fully below,the arrangement of the retractor 9720 and the shroud 9724 enable theretractor 9720 to expand to create an enlarged surgical field wherebysurgical procedures may be facilitated. The expandable shroud 9724enables the elongate body 9722 to be relatively simple while creating arelatively large surgical field and at the same time remaininglow-profile during insertion.

In some embodiments, the elongate body 9722 has a distal portion 9726and a proximal portion 9728 that are discrete members. In otherembodiments, the retractor 9720 has an elongate body 9722 that comprisesa portion similar to the distal portion 9726 without the proximalportion 9728. In other embodiments, the retractor 9720 has a portionsimilar to the proximal portion 9728 without the distal portion 9726.

In one embodiment, the distal portion 9726 comprises a first elongatedmember 9730 and a second elongate member 9732. The first and secondelongate members 9730, 9732 are generally semicircular in transversecross-section in one embodiment and are generally oval in anotherembodiment. The first and second elongate members 9730, 9732 can beother suitable shapes as well, such as any suitable oblong shape. In theillustrated embodiment, the first and second elongate members 9730, 9732are generally semicircular and have about the same radius of curvature.The first elongate member has a first elongate edge 9734 and the secondelongate member has a second elongate edge 9736.

The elongate body 9722 is able to be positioned in a multiplicity ofpositions, as discussed in greater detail below. One of the positions ofthe elongate body 9722 is a low-profile or closed position, which isshown in FIG. 232. In the low-profile position, the first longitudinaledge 9734 is positioned very close to the second longitudinal edge 9736.In one arrangement, a circle is defined within the first and secondelongate members 9730, 9732 when the elongate body is in the closedposition.

The elongate body 9722 also has an outer surface 9738 and an innersurface 9740. The inner surface 9740 at least partially defines apassage 9742 that provides access for a surgeon to a surgical locationso that a surgeon can perform a surgical procedure, as discussed herein.In one embodiment, the closed or low-profile configuration, the elongatebody 9722 fully encloses the passage 9782. As discussed more fullybelow, when the elongate body 9722 is in an expanded configuration, thepassage 9782 is only partially defined by the inside surface of theelongate body 9722. Two expanded configurations are illustrated in FIGS.233 and 234. In the illustrated embodiment, the inner surface of theelongate body is located on the first and the second elongate members9730, 9732.

As discussed above, in some embodiments, the elongate body 9722comprises discrete proximal and distal portions 9728, 9726. The proximalportion preferably comprises a first proximal side portion 9742 and asecond proximal side portion 9744. The first proximal side portion 9742has a third longitudinal edge 9746. The second proximal side portion9744 has a fourth longitudinal edge 9748. The first and second proximalside portions are movable relative to each other such that the third andfourth longitudinal edges 9750, 9752 can be positioned in closeproximity to each other or spaced apart, e.g., by a selected amount, asdiscussed more fully below.

In one embodiment, each of the first and second proximal side portions9742, 9744 has a corresponding inside surface 9750, 9752 that at leastpartially defining the passage. As discussed more fully below, theproximal portion 9728 is capable of having a circular transversecross-section in one configuration. The proximal portion 9728 preferablyalso is capable of having or at least partially defining an ovalconfiguration, or other suitable configuration, such as oblong, in otherembodiments.

Preferably the proximal portion 9728 is coupled with the distal portion9726 in a manner that permits the distal portion 9726 to pivot withrespect to the proximal portion 9728. The distal portion 9726 may beenabled to pivot by configuring the elongate body 9722 with one or morepivot joints 9754.

As discussed above, the retractor preferably includes an expandableshroud 9724. The shroud 9724 may be made of any suitable material thatcan stretch during expansion of the elongate body 9722 (or while theelongate body is in the enlarged configuration). In one embodiment, theshroud 9724 is coupled with the elongate body 9722. In one embodiment,the expandable shroud 9724 is an expandable sleeve that is positionedover the elongate body 9722. The shroud 9724 preferably is positionedover at least the distal portion 9726 where the elongate body 9722comprises proximal and distal portions 9728, 9726. In other embodiments,the expandable shroud 9724 is positioned over only one of the proximaland distal portions 9728, 9726 where both proximal and distal portions9728, 9726 form part of the retractor 9720.

In one arrangement, the expandable shroud 9724 is configured to extendat least from the first longitudinal edge 9734 to the secondlongitudinal edge 9736. In another embodiment, the expandable shroud9724 is configured to extend at least from the third longitudinal edge9746 to the fourth longitudinal edge 9748. In one arrangement, theexpandable shroud 9724 is configured to extend at least from the firstlongitudinal edge 9734 to the second longitudinal edge 9736 and from thethird longitudinal edge 9746 to the fourth longitudinal edge 9748. Insome embodiments, the expandable shroud 9724 does not extend all the wayaround the first and second elongate members 9730, 9732 or all the wayaround the first and second proximal side portions 9742, 9744.

In some embodiments, the retractor also includes a first linkage 9756that is coupled with the elongate body 9722. In one embodiment, thefirst linkage 9756 includes a first link member 9758 and a second linkmember 9760 that is coupled with the first link member 9758 at a pivotjoint 9762. The first link member 9758 may be coupled with the firstelongate member 9730 adjacent the first longitudinal edge 9734. Thesecond link member 9760 may be coupled with the second elongate member9732 adjacent the second longitudinal edge 9736. In the illustratedembodiment a second linkage member 9764 is provided and is coupled withthe elongate body 9722 on the opposite side of the elongate body 9722.

In one embodiment, the first linkage 9756 has a collapsed configuration(shown in FIG. 232) and extended configurations. A first extendedconfiguration is shown in FIG. 233 and a second extended configurationis shown in FIG. 234. As discussed above, in the illustrated embodiment,a corresponding second linkage 9764 is provided that couples a thirdlongitudinal edge 9766 and a fourth longitudinal edge 9768 of theelongate body 9722. The third longitudinal edge 9766 is located on anopposite side of the elongate body 9722 from the first longitudinal edge9734 and the fourth longitudinal edge 9768 is located on an oppositeside of the elongate body 9722 from the second longitudinal edge 9736.

The retractor of FIGS. 232-234 operates to provide access to a surgicallocation within a patient. In particular, the elongate body 9722 iscapable of having a low-profile configuration for insertion into thepatient. One suitable configuration for insertion is one wherein thepassage 9782 has a generally circular cross-section. This may beachieved by moving the first and second elongate bodies 9730, 9732and/or the first and second proximal side portions 9742, 9744 towardeach other until the longitudinal edges 9734, 9736 are adjacent to eachother. Other configurations may also be accommodated. For example, theinside surfaces of the elongate body 9722 can be configured with acurved transverse cross-section that is not circular.

Insertion of the retractor 9720 into the patient may be performed in anysuitable manner. For example, one or more dilators or obturators may beused to form an expanded channel into the patient, as discussed herein.As also discussed herein, where a retractor has a non-circularconfiguration, one or more dilators with non-circular transversecross-sectional profiles may be used.

Once the retractor 9720 is advanced to the surgical location within thepatient, the elongate body 9722 can be expanded. Where the technique forproviding access employs a retractor with discrete proximal and distalportions 9728, 9726, multi-stage expansion can be employed. For example,as shown in FIG. 233, the distal portion 9726 may be expanded from thelow-profile configuration to an enlarged configuration. In the enlargedconfiguration, the first longitudinal edge 9734 is spaced apart from thesecond longitudinal edge 9736. The expandable shroud 9724 is configuredto extend from the first longitudinal edge 9734 to the secondlongitudinal edge 9736 when the first and second edges 9734, 9736 arespaced apart. The shroud 9724 partially defines the passage 9782. In theexpanded configuration of FIG. 233, the cross-sectional area of thepassage 9782 at a first location 9770 is greater than thecross-sectional area of the passage 9782 at a second location 9772,wherein the first location 9770 is distal to the second location 9772.

The retractor 9720 may be actuated from the low-profile configuration tothe expanded configuration by any suitable technique. For example, thelinkages 9756, 9764 may be articulated to force the distal ends of thefirst and second elongate bodies 9730, 9732 apart. In one embodiment,the linkages 9756, 9764 are located outside the passage 9782. As aresult, the retractor 9720 is configured to be expanded from the outsideof the passage 9782. This advantageously enables all the space in thepassage 9782 to be used for procedures. In another embodiment, thelinkages 9756, 9764 are located within the passage 9782. Thisarrangement is advantageous in that the linkages can more freely rotatein the enclosed space. In another embodiment, the linkage may be partlywithin the passage and partly outside to provide a combination of thesebenefits while maintaining the retractor in a relatively low-profile.

FIG. 234 illustrates a second stage of expansion of the retractor 9720.In particular, the proximal portion 9728 has been actuated to increasethe size of the passage 9782 in the proximal portion 9728. This isachieved by moving the proximal side portions 9742, 9744 away from eachother. In this expanded configuration, the linkages 9756, 9764 generallymaintain the same position as is shown in the first stage of expansionof FIG. 233. As a result, the first and second elongate members 9730,9732 are tilted so that the outside surfaces thereof are at a less-steepangle. This tilts the distal edges of the first and second elongatemembers 9730, 9732 to a generally flat orientation (e.g., in or nearlyin a plane perpendicular to a longitudinal axis of the passage 9782).

The retractor 9720 provides for multi-state expansion while maintainingthe passage 9782 in a substantially entirely enclosed configuration. Theexpanded or enlarged configurations enable procedures to be performedacross one, two, three, or more than three adjacent vertebrae. Theretractor 9720 can also be only partially expanded as is needed for theprocedure.

Embodiments having an expandable shroud can also be employedadvantageously in procedures such as the lateral or postero-lateralplacement of replacement disks, as well as other developing procedures.FIG. 234A illustrates methods of applying an implant 9790, e.g. anintervertebral replacement disc, through the retractor 9720. Somemethods for applying an implant are described further in U.S. patentapplication Ser. No. 10/842,651, filed May 10, 2004, which is herebyincorporated by reference herein in its entirety. With reference to FIG.234A, the retractor 9720 preferably is actuated to the expandedconfiguration and the implant 9790 is delivered laterally as indicatedby the arrow 9794 to a surgical location defined by the distal portion9726 of the retractor 9720 at one lateral side of the vertebra V1 andinto an interbody space I. In other techniques alternative approachescan be used. In one application, in order to facilitate insertion of theimplant 9790, visualization of the surgical site may be achieved in anysuitable manner, e.g., by use of a viewing element, as discussed herein.In one procedure, a gripping apparatus 9792, is coupled with one or moreportions and/or surfaces of the implant 9790 to facilitate insertion ofthe implant 9790. The gripping apparatus 9792 and the implant 9790 areadvanced through the proximal portion 9728 of the retractor 9720,through the surgical space, and into the interbody space I to deliverthe implant 9790. In some embodiments, the method of applying an implant9790 can be performed using other retractors or access devices describedherein.

The retractor 9720 is particularly advantageous for delivering implantsthat are elongated. For example, some replacement discs are generallyplanar structures that are elongated in at least one dimension. Theexpandability of the proximal portion 9728 facilitates insertion of suchan elongated implant. The proximal portion 9728 can be expanded suchthat the passage defined therein is long enough along the direction ofexpansion to accommodate a long dimension of an elongated implant. Thedegree of expansion of the proximal portion 9728 can be decreased afterthe elongated implant reaches the distal portion 9726 of the retractor9720. This reduces the length of time that the skin and adjacent tissueis expanded in the region of the proximal portion 9728. In anothertechnique, an implant that is elongated in at least one dimension can beoriented during delivery through the retractor 9720 such that the longdimension of the implant is transverse to the direction of expansion ofthe proximal portion 9728. In one technique, the proximal portion 9728is expanded so that a gap at least as wide as the thickness of theimplant is formed and is covered by the shroud 9724. The shroud 9724 canbe configured to be flexible enough so that it can be deflected outward(e.g., perpendicular to the direction of expansion of the proximalportion 9728) to accommodate an implant with a long dimension that isgreater than the width of the passage 9784 when the shroud 9724 is notdeflected. Thus, an implant with a long dimension greater than the widthof the elongate body 9722 in the proximal portion 9728 of the retractor9720 can be delivered in a transverse orientation.

FIGS. 235-239 show another access device or retractor 9800 that isparticularly advantageous in some application for retracting tissue toprovide access to a surgical location (e.g., a spinal location) within apatient. The retractor 9800 is similar to the access devices describedabove in connection with FIGS. 123-150, except as set forth below. Onefeature of the retractor 9800 is that a proximal portion thereof is ableto tilt relative to a distal portion to provide enhanced visibility of asurgical location (e.g., adjacent a spinal location), particularly ofthe far reaches of a surgical field exposed by the retractor 9800. Asdiscussed further below, the proximal portion is able to tilt about atleast two axes in one embodiment.

The retractor 9800 generally includes an elongate body 9804 and apassage 9808. The elongate body 9804 has a proximal portion 9812 and adistal portion 9816 in one embodiment. Where proximal and distalportions 9812, 9816 are provided these portions may be discrete portionsof the elongate body 9804 or may be discrete, contiguous, or remoteregions thereof. As with many of the embodiments described herein, theretractor 9800 can be configured such that the cross-sectional area ofthe passage 9808 at a first location is greater than the cross-sectionalarea of said passage at a second location, where the first location isdistal to the second location. When in this expanded configuration, atleast one of (and preferably both of) the first and the second locationsare in the distal portion 9816. This configuration may be achieved byany suitable technique, such as those described herein (e.g., byexpanding the distal portion 9816 with an expander tool).

The elongate body 9804 defines a length 9820 between the proximalportion 9812 and the distal portion 9816 along a longitudinal axis 9824.The length 9820 is sufficient such that the distal portion 9816 can bepositioned inside the patient adjacent the spinal location while theproximal portion 9812 is accessible. The proximal portion 9812preferably is accessible to the surgeon during a surgical procedure. Insome applications, the retractor 9800 is applied such that at least aportion of the proximal portion 9812 remains outside the patient's bodyduring the procedure.

In one embodiment, the elongate body 9804 is configured such that atransverse cross-section thereof has a first dimension 9828 that islonger than a second dimension 9832. The first dimension 9828 isperpendicular to the second dimension 9832. In one embodiment, thetransverse cross-section of the elongate body 9804 or of the proximalportion 9812 is generally oblong. In another embodiment, the transversecross-section of the elongate body 9804 or of the proximal portion 9812is generally oval. In another embodiment, the transverse cross-sectionof the elongate body 9804 or of the proximal portion 9812 is generallycircular.

The passage 9808 extends through the elongate body 9804 between theproximal portion 9812 and the distal portion 9816. Preferably, thepassage 9808 is sized such that a plurality of surgical instruments maybe advanced to the surgical location in connection with any suitablesurgical technique, such as those disclosed herein. In some techniques,it is advantageous to be able to advance more than one surgicalinstrument through the passage 9808 at the same time. Advancement ofsurgical instruments to the surgical location may be facilitated byproviding a generally smooth inside surface 9840 in the elongate body9804.

The elongate body 9804 is configured such that the proximal portion 9812may be tilted relative to the distal portion 9816 in a first directiongenerally aligned with the first dimension 9828 and in a seconddirection generally aligned with the second dimension 9832. In oneembodiment, the elongate body 9804 is configured such that a portion ofthe elongate body 9804 may be rotated about a first axis 9844 such thatthe proximal portion 9812 may be tilted relative to the distal portion9816. Also, the elongate body 9804 may be configured such that a portionof the elongate body 9804 may be rotated about a second axis 9848 suchthat the proximal portion 9812 may be tilted relative to the distalportion 9816. In this arrangement, the first axis 9844 is perpendicularto the second axis 9848. The tilting about the second axis isillustrated in FIG. 238, where a longitudinal axis 9824 a of a portionof the passage 9808 corresponding to the proximal portion 9812 of theretractor 9800 is shown at an angle of a relative to the longitudinalaxis 9824 of the elongate body 9804. In this position, visibility of aportion of the surgical field adjacent a lateral (or medial) side of theretractor 9800 may be enhanced. A second dashed line is shown in FIG.238 opposite the longitudinal axis 9824 a on the opposite side of thelongitudinal axis 9824. This dashed line represents a range of motion ofthe proximal portion 9812 tilted to the opposite side about the axis9848.

In one embodiment, the retractor 9800 has a coupling 9860 to enabletilting of the proximal portion 9812 relative to the distal portion9816. The coupling 9860 preferably is located between the proximal anddistal portions 9812, 9186. The coupling 9860 includes a gimbal ring9864 and a plurality of pivot joints 9868 in one embodiment. The gimbalring 9864 can take any suitable form and generally is an intermediatestructure that enables the proximal and distal portions 9812, 9816 tonot be directly coupled together so that they may be independentlytilted about at least two axes. The gimbal ring 9864 preferably includesa first pair of apertures 9870 on opposite sides thereof. The firstpivot axis 9844 may extend through the first pair of apertures 9870. Thegimbal ring 9864 can also include a second pair of apertures 9872located on opposite sides thereof. The second pivot axis 9848 may extendthrough the second pair of apertures 9872. The first pivot axis 9844 isperpendicular to the second pivot axis 9848 in one embodiment.

The pivot joints 9868 may include a member 9874 about which at least oneof the gimbal ring 9864, the proximal portion 9812, and the distalportion 9816 can rotate. The member 9874 can be any suitable structureand in one embodiment is a rivet.

To assemble the retractor 9800, a member 9874 is extended through eachof the apertures 9872 and a corresponding pair of apertures 9876 in theproximal portion 9812 and another member 9874 is extended through eachof the apertures 9870 and a corresponding pair of apertures 9878 in thedistal portion 9816. This arrangement of the retractor 9800 isrelatively simple and thus can be easily assembled and used. Also, thisarrangement provides the advantage of being able to enhance thevisibility of the outer edges of the retractor 9800 when it is expandedby enabling the proximal portion 9812 of the elongate body 9804 to betilted relative to the distal portion 9816, which is generally fixed inposition when deployed within the patient.

Another embodiment that is similar to the embodiment discussed above inconnection with FIGS. 235-239 is the embodiment discussed in connectionwith FIG. 207, wherein a ball joint-like arrangement is provided. Thisarrangement provides a first semi-spherical surface and a secondsemi-spherical surface. The second semi-spherical surface is configuredto mate with the first semispherical surface and to enable a proximalportion of a retractor to be tilted relative to a distal portion thereofin a multiplicity of positions.

In another embodiment, the retractor 9800 does not have discreteproximal and distal portions 9812, 9816. Rather, a portion of theelongate body 9804 is made more flexible than the rest of the elongatebody. The more flexible section is large enough and flexible enough toenhance visibility of the surgical field to an extent similar to thatprovided by the coupling and pin joint embodiments and to the ball jointembodiments discussed above. The more flexible section, in oneembodiment, comprises a bellows that can expand and contract in responseto a force being applied near the proximal end of the elongate body. Inone arrangement, the bellows is configured so that a minimum force isrequired to begin to tilt the proximal portion so that the proximalportion will hold its position unless the surgeon desires to repositionit.

FIGS. 240-241 illustrate an obturator 9900 coupled with an access device9902. In some embodiments, an obturator 9900 and a retractor, or anaccess device 9902, can be assembled and packaged together in a kit tobe readily inserted into a patient. In such an embodiment, the accessdevice 9902 is packaged in a generally tubular unexpanded shape. Theproximal portion 9904 of the obturator can comprise handgrip features9906, such as raised or lowered gripping portions, to facilitatemanipulating and inserting the access device 9902 into the patient. Insome embodiments, the obturator 9900 comprises a ledge 9928 to interfacewith the proximal end 9910 of the access device 9902. In someembodiments, the obturator 9900 can be cannulated 9912 for optional useover sequential dilators. The obturator 9960 can be used in expandablespinal access systems. The obturator 9900 can have a round or oblongshaped cross-section. With reference to FIGS. 242-243, in oneembodiment, an obturator 9920 can be used for insertion of a multi-pivotoval access device 9922, such as that described with reference to FIGS.235-239.

FIGS. 244-284 illustrate some additional embodiments of access devicemounting fixtures. According to some embodiments, a viewing element or aviewing element mounting fixture can be provided for use with an accessdevice. Viewing elements or viewing element mounting fixtures cancomprise different configurations and structures. Some embodiments ofviewing elements or viewing element mounting fixtures can comprise forexample, ball joints that rotate and pivot, coiled springs, slidingrails, planetary gears, hose clamps, split shaft collars,spirograph-type configurations, and C-linkage type configurations. Stillother embodiments are contemplated. Viewing element and viewing elementmounting fixtures will be described in more detail below. Additionally,other types of mounting fixtures and support elements will be described.

As discussed above, the access devices described herein may beadvantageously incorporated into a surgical assembly, similar to thesurgical assembly 9000 illustrated in FIG. 182. This arrangement freesup the hands of the surgeon and provides stability to the access device9006 and the space created for surgical procedures, among otheradvantages. One approach to incorporating the access devices into asurgical assembly is to provide an access device mounting fixture.

FIG. 244 shows one embodiment of a viewing element mount 10040 thatprovides adjustable, e.g., slidable, coupling of a viewing element 10042to an access device or an access device mounting fixture (not shown). Inthe illustrated embodiment, the viewing element mount 10040 includes acarrier arm 10044, a support ring 10048, and a viewing element joint10052. The carrier arm 10044 has an elongate shape with a proximal end10056 and a distal end 10060. The carrier arm 10044 preferably also hasan adjustment slot 10064 extending between the proximal and distal ends10056, 10060. The adjustment slot 10064 permits the carrier arm 10044 totranslate with respect to the support structure, as indicated by anarrow K and to pivot. Preferably a locking mechanism 10068 is provided,such as a lock knob, about which the carrier arm 10044 can be rotated,as indicated by arrows L.

The support ring 10048 is an annular member, in one embodiment, thatdefines an aperture 10072. The aperture 10072 provides a tool path andsight line opening through which a surgical location can be accessedand/or monitored. Preferably, the support ring 10048 is rotatable aboutan axis 10076 (which may correspond with the center of the tool path andsight line) extending through the center of the aperture 10072, asindicated by arrows M. The rotation of the support ring 10048 permitsthe rotatable adjustment of the viewing element 10042 about a proximalportion of an access device.

In one embodiment, the viewing element joint 10052 is supported by thesupport ring 10048 at a location near the aperture 10072. The viewingelement joint 10052 is a ball joint in one embodiment. One skilled inthe art should recognize that a ball joint will provide pitchadjustment, as indicated by arrows N, yaw adjustment, as indicated byarrows O, and roll adjustment, as indicated by arrows P, to the viewingelement 10042. In one form, the ball joint also provide translationalelevation adjustment, as indicated by arrows Q. In one embodiment, thetranslation of the viewing element 10042 is achieved by rotationaladvancement, e.g., by way of mating threads, as indicated by the helicalarrow Q′.

The viewing element mount 10040 advantageously provides flexibleadjustment of the viewing element 10042, after which the viewing element10042 can be focused via a focusing knob 10080.

FIG. 245 shows another embodiment of a surgical assembly 10100 that issimilar to the surgical assembly 9000. The surgical assembly 10100includes a linkage 10104 that connects a viewing element support 10108to a surgical assembly support 10112. The linkage 10104 is any suitablemechanical coupling that extends from the surgical assembly support10112 to a location above an access device 10114. The linkage 10104movably supports the viewing element support 10108, and thereby movablysupports a viewing element 10116.

The linkage 10104 preferably is a two member linkage that permits a widerange of positioning of the viewing element support 10108 in twodimensions. The viewing element support 10108 is preferably rotatablycoupled with one end of the linkage 10104, as is illustrated by arrowsR. In one embodiment, the viewing element support 10108 is a cameramount. The viewing element 10116 can be rotated about an axis 10120 thatextend through the viewing element 10116 and the viewing element support10108. The surgical assembly 10100 thus is able to provide flexiblepositioning of the viewing element 10116 with respect to an accessdevice 10124.

FIG. 246 is another embodiment of a surgical assembly 10140 that issimilar to the surgical assembly 9000, except as set forth below. Thesurgical assembly 10140 includes a surgical assembly support 10144, anaccess assembly 10148, and a viewing assembly 10152. The access assembly10148 and viewing assembly 10152 are coupled with a distal end of thesurgical assembly support 10144. The access assembly 10148 includes anaccess device or retractor 10156 and an access device mounting fixture10160.

The viewing assembly 10152 includes a viewing element 10162, an elongatemember 10164 and an arcuate member 10168 located on the distal end ofthe elongate member 10164. The elongate member 10164 is translatablycoupled with the distal end of the surgical assembly support 10144, asindicated by arrows S. The viewing element 10162 is coupled with thearcuate member 10168, preferably by way of a viewing element mount10170, for translation about the arcuate member 10168, as indicated byarrows T. The motion indicated by the arrows S and T allows the viewingelement 10162 to be positioned as desired in any location about theproximal end of the access device 10156.

FIG. 247 is another embodiment of a surgical assembly 10180 that issimilar to the surgical assembly 9000, except as set forth below. Thesurgical assembly 10180 includes a surgical assembly support 10184, anaccess assembly 10188, and a viewing assembly 10192. The access assembly10188 and viewing assembly 10192 are coupled with a distal end of thesurgical assembly support 10184. The access assembly 10188 includes anaccess device or retractor 10196 and an access device mounting fixture10200. The access device 10198 may be any suitable access device.

The viewing assembly 10192 includes a viewing assembly support arm10204, a viewing element support fixture 10208 coupled with a distal endof the viewing assembly support arm 10204, and a viewing element mountedin the viewing element support fixture 10208. The proximal end of theviewing assembly support arm 10204 is coupled with a positioning element10212. The positioning element 10212 includes a wheel 10216 in one formthat is rotatably coupled with the surgical assembly 10180 at a firstlocation 10220 near an outer perimeter thereof. The viewing assemblysupport arm 10204 is rotatably coupled with the wheel 10216 at a secondlocation 10224 spaced from the first location 10220. The first andsecond locations 10220, 10224 are selected to provide a wide range ofpositions about the proximal end of the access device 10196, two ofwhich are illustrated in FIG. 248.

FIG. 249 illustrates a portion of another embodiment of a surgicalassembly. In particular, a viewing assembly 10240 includes a viewingelement 10244 and a viewing element support 10248. The viewing elementsupport 10248 includes a track 10252 with gear teeth 10254 and a race10256, in one embodiment. The gear teeth 10254 are configured to matewith gear teeth 10262 of an internal gear 10264. The viewing element10244 is coupled with the internal gear 10264 whereby the viewingelement 10244 may be positioned about the track 10252 at any desiredlocation.

With reference to FIGS. 250-251, a viewing element support mount 10280comprises a scope mounting hole 10282 coupled with an expandable andcontractible clamping element 10284. The clamping element 10284 has aplurality of notches or holes 10286. The clamping element 10284 can beadjusted to fit around a proximal portion of an access device. Theclamping element 10284 is adjustable to accommodate proximal portionshaving different shapes or sizes. A gear or ratchet mechanism 10288 canbe coupled with the clamping element 10284 to adjust the size of theclamping element 10284. The clamping element 10284 can be used withoblong shaped access devices, as well as with circular shaped accessdevices.

With reference to FIGS. 252-253, a viewing element support assembly10300 is illustrated. A viewing element 10302 is configured to bereceived in a viewing element support block 10304. The viewing elementsupport block 10304 comprises a clamp 10306 and a clamp release button10308. The viewing element support block 10304 can be inserted onto aviewing element support platform 10310. The viewing element supportplatform 10310 preferably is configured to be coupled with a proximalportion of an access device 10314. In the illustrated embodiment, theviewing element support platform 10310 has a slot 10312 with a T-shapedcross-section for receiving a clamping member 10306 of the viewingelement support block 10304. When the clamp member 10306 of the viewingelement support block 10304 is placed in the viewing element supportplatform 10310, and into the T-shaped slot 10312, the viewing elementsupport block 10304 can be positioned at a plurality of locations in theT-shaped slot 10312. The viewing element support block 10304 can bepositioned around the periphery of the proximal portion of the accessdevice 10314. The viewing element 10302 can be positioned within theaccess device 10314 at any desired location. The viewing element supportblock 10304 can be repositioned within the T-shaped slot 10312 bypressing the clamp release button 10308 and moving the viewing elementsupport block 10304. When a desired position is achieved, the clamprelease button 10308 is released and the clamp 10306 preferably clampsto the T-shaped slot 10312. The embodiment shown in FIGS. 252-253provides for positioning of viewing elements in desired locations withinthe access device.

With reference to FIGS. 254-255, another embodiment of viewing elementsupport portion 10320 is illustrated. The viewing element 10322 isconfigured to be received in the viewing element support block 10324.The viewing element support block 10324 has a C-shaped clamp 10326 and aclamp release button 10328. In the illustrated embodiment, the viewingelement comprises a camera 10330. The viewing element support block10324 is configured to be coupled with a viewing element supportplatform 10332. The C clamp 10326 of the viewing element support block10324 can be positioned over an edge 10334 of the viewing elementsupport platform 10332. The viewing element 10322 can extend into anopening 10336 in the viewing element support platform 10332 and into anaccess device 10338. The viewing element support block 10324 can beunclamped from the viewing element support platform 10332 andrepositioned to various locations on the viewing element supportplatform 10332.

With reference to FIG. 256, one embodiment of viewing element supportmount 10340 has a viewing element 10342 coupled with a viewing elementsupport block 10344. The viewing element 10342 in some embodiments caninclude a camera 10346. The viewing element support block 10344 cancomprise an air pressure port 10348 and an air pressure release valve10350. In the illustrated embodiment, the viewing element support block10344 is coupled with a viewing element support platform 10352 bycreating a vacuum between the viewing element support platform 10352 andthe viewing element support block 10344. The viewing element supportplatform 10352 in one embodiment has a substantially smooth surface. Theviewing element support platform 10352 has an opening 10354 configuredto receive a proximal portion of an access device 10356. The viewingelement support block 10344 is positioned in a desired location on theviewing element support platform 10352 so that the viewing element 10342can be positioned within the access device 10356 for viewing thesurgical location. FIG. 257 is a side view of the viewing elementsupport mount 10340 in FIG. 256. With reference to FIG. 257, a cavity10358 is provided for generating the vacuum with sealed portions 10360surrounding the cavity.

With reference to FIGS. 258-259, a viewing element support mount 10380has a viewing element 10382 coupled with a viewing element support block10384 having a suction cup 10386. The suction cup 10386 of the viewingelement support block 10384 is configured to be coupled with a viewingelement support platform 10388. In one embodiment, the viewing elementsupport platform 10388 is formed with a polished glass plate. Theviewing element support block 10384 has a suction release button 10390to enable to the viewing element support block 10384 to be removed andrepositioned on the viewing element support platform 10388. In someembodiments, the viewing element 10382 can comprise a camera 10392. Theviewing element support block 10384 can be coupled with the viewingelement support platform 10388 at various locations.

FIGS. 260-261 illustrates another embodiment of a viewing elementsupport mount 10400 having a viewing element support block 10404 with asuction cup 10402. The viewing element support block 10404 is shown indifferent states. The viewing element support block 10404 has a suctioncup 10402 in a free state 10406 with a spring 10408 in tension. Theviewing element support block 10404 is shown in a compression state10410 with the controls 10408 released. Following the compression state10410, the viewing element support block 10404 is in a suction state10414 and is coupled with a viewing element support platform 10416.Actuating the controls 10412 causes the device to pull up on the lip ofthe suction cup 10402 to release the suction at the release state 10418.The viewing element support block 10404 is then returned to the freestate 10406. Any other suitable coupling method can be used for couplinga viewing element to a viewing element support mount.

With reference to FIG. 262, an access device 10440 has a fixed proximalportion 10442 coupled with a viewing element 10444 and a viewing elementsupport mount 10446. The viewing element 10444 can be coupled with theviewing element support mount 10446 with a ball joint to enable theviewing element 10444 to pivot and rotate relative to the viewingelement support mount 10446 and the access device 10440. In otherembodiments, the proximal portion 10442 of the access device 10440 canbe rotated and/or pivoted.

FIGS. 263-264 show further embodiments of viewing assemblies foradjustably coupling a viewing element to an access device mountingfixture. FIG. 263 shows a surgical assembly 10460 that is similar to thesurgical assembly 9000, except as set forth below. The surgical assembly10460 includes a surgical assembly support and an access assembly inphantom, and a viewing assembly 10464. The access assembly and viewingassembly 10464 are coupled with a distal end of the surgical assemblysupport.

The viewing assembly 10464 is coupled with the surgical assembly in asuitable manner. For example, in one embodiment, the viewing assembly10464 is coupled with a portion of an access assembly. In oneembodiment, a ball joint connection 10468 is provided between theviewing assembly 10464 and a jaw 10472 of an access device mountingfixture. A linkage 10476 preferably extends between the ball jointconnection 10468 and a viewing element 10480. In the embodiment of FIG.263, the linkage 10476 comprises a first member 10484A, a second member10484B, and a third member 10484C. Each of the first, second, and thirdmembers 10484A, 10484B, 10484C are coupled by ball joints 10488A,10488B. The viewing element 10480 can be coupled with the member 10484Cby way of a ball joint 10492. Arrows 10496 indicate that the viewingelement 10480 is adjustable in pitch, yaw, roll, and elevation. FIG. 264illustrates a similar arrangement wherein a two member linkage isprovided. The two members of the linkage are joined by a ball joint.

The ball joint and linkage systems shown in FIGS. 263-264 can includepneumatic or hydraulic actuation and position control. FIGS. 265-266illustrate one such arrangement. FIG. 265 illustrates a linkage 10500that includes a first member 10504 and a second member 10508 joined by aball joint 10512. The position of the first member 10504 and the secondmember 10508 can be fixed by any suitable means, such as by a clamp10514. The second member 10508 includes a body portion 10520, a clampingjaw 10524, and a clamp pivot 10528 about which the body portion 10520and the clamping jaw 10524 pivot under pneumatic or hydraulic actuation.

The ball joint 10512 is shown in greater detail in FIG. 266. The balljoint includes a ball 10532, a clamping socket 10536 and a series ofpassages. A first passage 10540 extends through the ball 10532 betweenthe clamping socket 10536 and the first member 10504. Fluid may beconducted downstream from the ball 10532 to another ball joint or otherlinkage member. The upstream end of the first passage 10540 nearest tothe clamping socket 10536 communicates with a second passage 10544 thatis located between the ball 10532 and the clamping socket 10536. Thesecond passage communicates with a third passage 10548 extending betweenthe second passage 10544 and a fourth passage 10552 formed between thebody portion 10520 and the clamping jaw 10524. An O-ring seal 10556 (orany other suitable sealing arrangement) may be provided to force a fluidin the fourth passage 10552 into the third passage 10548. A fifthpassage 10560 communicates with the fourth passage 10552 and extendsinto the body portion 10520. The fifth passage 10560 is in fluidcommunication with a source of fluid pressure.

The series of passages shown in FIG. 266 enable clamping of the balljoint 10512. In one arrangement, fluid pressure is dissipated in thepassages, allowing the ball 10532 to move freely in the ball joint10512. The first member 10504 (which may be coupled with a viewingelement) may then be repositioned with respect to the second member10508. When the desired position is reached, the fluid pressure in thepassages may be applied. This pressure is communicated to the secondpassage 10544 wherein the pressure is applied to the side of the ball10532 opposite the first member 10504. The ball 10532 is thereby forcedup against the body portion 10520 of the second member 10508. Thepressure of the ball 10532 up against the body portion 10520 of thesecond member 10508 causes the ball 10532 to be immobilized temporarily.The fluid used to actuate the clamping may be gas, e.g., air, or liquid,e.g., water.

The pneumatic or hydraulic actuation and position control arrangement ofFIGS. 263-266 preferably is able to hold securely the weight of asurgical viewing element, such as a camera and/or a fiber light cable.The arrangements of FIGS. 263-266 advantageously keep the mountingfixtures out of tool path and sight lines. Another approach for clampingthe viewing assemblies of FIGS. 263-266 would employ a friction fit,alone or in combination with a pneumatic or hydraulic fluid clamp.

FIG. 267 is a top view of one embodiment of an access device mountingfixture 10600 for adjustably mounting an access device. The accessdevice mounting fixture 10600 includes a first jaw 10604 and a secondjaw 10608. The first and second jaws 10604, 10608 are configured tocouple to an access device in a suitable manner, e.g., to clamp anaccess device, to adjustably mount an access device, etc.

The access device mounting fixture 10600 also includes means to adjustthe position of the jaws 10604, 10608 with respect to each other. In oneform, the mounting fixture 10600 includes a box joint pivot 10612 thatis actuated by a screw and nut arrangement 10616. In particular, asupport arm 10620 extends proximally of a pivot location 10624. Thefirst jaw 10604 extends between a proximal end 10628, which is coupledwith the support arm 10620 at the pivot location 10624, and a distal end10632, which is configured to be coupled with an access device. Thefirst jaw 10604 has a bore 10636 extending transversely therethrough ata location between the proximal end 10628 and the distal end 10632. Thebore 10636 is configured to receive a portion of the screw and nutarrangement 10616 for adjustment of the access device mounting fixture.The jaw 10604 also includes an access device engagement portion 10640near the distal end 10632. The access device engagement portion 10640preferably has an arcuate inside shape, which is circular in oneembodiment. Other suitable shapes, such as oval shapes, may also beemployed in connection with the access device engagement portion 10640.Further details of the engagement portion 10640 are discussed below inconnection with FIG. 269.

The second jaw 10608 extends between a proximal end 10644, which iscoupled with the support arm 10620 at the pivot location 10624, and adistal end 10648, which also is configured to coupled with an accessdevice. The pivot jaws 10604, 10608 are thus enabled to pivot withrespect to each other and are supported proximally by the support arm10620. The first jaw 10608 has a bore 10652 extending transverselytherethrough at a location between the proximal end 10644 and the distalend 10648. The bore 10652 is configured to receive a portion of thescrew and nut arrangement 10616 for adjustment of the access devicemounting fixture 10600. The jaw 10608 also includes an access deviceengagement portion 10656 near the distal end 10648. The access deviceengagement portion 10656 preferably has an arcuate inside shape, whichis circular in one embodiment. Other suitable shapes, such as ovalshapes, may also be employed in connection with the access deviceengagement portion 10656. Further details of the engagement portion10656 are discussed below in connection with FIG. 269.

In one form the screw and nut arrangement 10616 includes an advancementelement 10660 which is connected to a screw 10664. The advancementelement 10660 preferably is a side-mounted wheel. The screw 10664 isthreaded and is sized to extend through the bore 10652 and at leastpartially through the bore 10636. The bore 10636 preferably is sized toreceive a ball nut 10668 which has threads that engage threads on thescrew 10664. Thus by turning the side-mounted wheel, the ball nut 10668is advanced toward the wheel, which causes the jaws 10604, 10608 to beadvanced toward each other. Advancement of the jaws 10604, 10608 causesthe access device engagement portions 10640, 10658 to be advanced towardeach other, which could cause an access device coupled therewith to bereduced in size, e.g., un-expanded. If the jaws 10604, 10608 are movedin the opposite direction, an access device coupled therewith would beexpanded thereby.

FIG. 268 shows another embodiment of an access device mounting fixture10680, which is similar to the mounting fixture 10600 except as detailedbelow. The mounting fixture 10680 includes a first jaw 10684, a secondjaw 10688, and a jack screw arrangement 10692 that is coupled with thejaws 10684, 10688 such that the jack screw 10692 can actuate the jaws10684, 10688. A double arrow J illustrates that motion of the jaws10684, 10688 away from each other enables expansion of an access device,such as the access devices described or incorporated by referenceherein.

FIG. 269 is a detail view of an access device engagement portion 10696of the jaw 10688. The cross-sectional profile of the engagement portion10696 may take the form of an inverted “J”. This arrangement provides achannel 10704 that extends around the bottom surface of the jaw 10684. Asimilar channel may be formed on the jaw 10684 such that when the jaws10684, 10688 are brought together completely, a circular channel isformed on the bottom surface of the mounting fixture 10680. The shape ofthe channel 10704 need not be circular. The channel shape could be anyshape that corresponds with a shape of a proximal end of an accessdevice. In another embodiment, the engagement portion 10696 may berelatively short, forming a hook-like feature.

As shown in FIG. 269, the channel 10704 is configured to receive aproximal end 10708 of a proximal portion 10712 of an access device10716. One skilled in the art should recognize that further clampingdevices can be provided to maintain the elevation of an access devicewith respect to the mounting fixture 10680. Also, in some procedures,the patient may at least partially support the access device.

FIG. 270 shows another embodiment of an access device mounting fixture10740. The access device mounting fixture 10740 is similar to thosehereinbefore described, except as set forth below. The access devicemounting fixture 10740 includes a first jaw 10744 and a second jaw10748. The first and second jaws 10744, 10748 are translatably mounted,such that the second jaw 10748 may be moved at least between a firstposition 10752 and a second position 10756. The first position 10752corresponds to an un-expanded position (e.g., an un-expanded position orconfiguration of an access device). The second position 10756corresponds to an expanded position (e.g., an expanded position orconfiguration of an access device).

One embodiment of a translatable coupling of the jaws 10744, 10748 isillustrated in FIG. 70. A pin 10760 is received within correspondingrecesses 10764A, 10764B formed in the first and second jaws 10744,10748. In the illustrated embodiment, the pin 10760 is positioned distalof an access device engagement portion of the jaws 10744, 10748, but thepin 10760 could be located elsewhere as well. A translation actuator10768 is located near a proximal end of the jaw 10748. The translationactuator 10768 can take any form, e.g., a screw that engages threadsassociated with the jaw 10744. The translation actuator 10768 has awheel 10772 for advancement in one embodiment. The translatable couplingof the access device mounting fixture 10740 provides linear motion ofthe jaw 10744 with respect to the jaw 10748.

FIGS. 271-272 show one embodiment of a viewing element mount 10800. Theviewing element mount 10800 provides adjustable coupling of a viewingelement 10802 to an access device or an access device mounting fixture.The viewing element mount is spring loaded and can be positioned in acontracted configuration or an expanded configuration. In a contractedconfiguration, spring loaded elements 10804, 10806 are compressed andside portions 10808, 10810 of the mount are positioned near one another.The contracted mount 10800 preferably can engage an access device havingan expandable proximal portion when the access device is in thecontracted configuration. When the access device is to be expanded atthe proximal portion, the support mount 10800 can also be positioned inan expanded configuration. The side portions 10808, 10810 of supportmount can be separated. The spring loaded elements 10804, 10806preferably snap into position between the side portions 10808, 10810 tomaintain a generally continuous surface around the proximal portion ofthe access device for mounting or supporting the viewing element 10802when the access device and the support mount 10800 are in expandedconfigurations. In the illustrated embodiment, the viewing element 10802has a pair of adjustable roller mounts 10812, 10814, for engaging thesupport mount 10800.

With reference to FIG. 273, a viewing element support mount 10820comprises first and second side portions 10822, 10824. The viewingelement support portion 10826 is expandable from a contractedconfiguration to an expanded configuration. Side portions 10822, 10824are coupled with one another via a linkage mechanism 10828. In acontracted configuration, the first and second side portions 10822,10824 are positioned generally near one another and the linkagemechanisms 10828 are in a generally folded position. In the expandedconfiguration, the first and second side portions 10822, 10824 arespaced from one another and the linkage mechanisms 10828 are in anextended locked position. In the expanded configuration, the linkagemechanisms 10828 in the locked configuration form a continuous surface10830 between the top of the first side portion 10822 and the top of thesecond side portion 10824 such that a viewing element can be mounted atvarious positions along the expanded viewing element support portion10826.

With reference to FIG. 274, another embodiment of an expandable viewingelement support mount 10840 is illustrated. In the viewing elementsupport mount 10840 of the illustrated embodiment, side portions 10842,10844 of the viewing element support mount 10840 have a generallyC-shaped cross-section. A coiled spring 10846 is deployed within theside portions 10842, 10844 of the viewing element support mount 10840. Aviewing element 10848 is configured to slide relative to the sideportions 10842, 10844 of the viewing element support mount 10840 whenthe viewing element support mount 10840 is in the expandedconfiguration. The coiled spring 10846 can actuate the side portions10842, 10844 of the viewing element support mount 10840 between thefirst configuration and the second configuration.

With reference to FIG. 275, in one embodiment of a viewing elementsupport mount 10860 a proximal portion 10862 of the support mount 10860comprises a ball joint 10864 and a jack screw 10866 for manipulating theviewing element support mount 10860 to a desired position relative anyaccess device. Near a distal end 10868 of the viewing element supportmount 10860, an extended visualization window 10870 is provided.Additionally, a viewing element pivot mount 10872 is placed in a distalportion of the viewing element support mount 10860.

With reference to FIGS. 276-280, another embodiment of a viewing elementsupport mount 10880 is illustrated. The viewing element support mount10880 includes a ball joint 10882 at a proximal portion of the handle10884. A jack screw 10886 is also provided to provide elevation androtation of the viewing element support mount 10880. The viewing elementsupport mount 10880 has an arm portion 10888 that extends downwardtoward an access device coupling location 10890. The viewing element10892 can be rotated in the viewing element support location 10894. Inone embodiment, the viewing element support mount 10880 can be coupledwith a generally oval-shaped proximal portion of an access device 10896.The viewing element support mount 10880 can be pivoted or rotated tomove the viewing element 10892 to various positions along the proximalportion of the access device 10896. In one embodiment, a viewing elementsupport portion 10898 can swing approximately 60 degrees to follow alonga sidewall of an oval-shaped collar of an access device 10896. In oneembodiment, the viewing element 10892 comprises a camera. In someembodiments, the camera can have approximately 300 degrees of rotarytranslation about the axis of the scope as shown in FIG. 277. In oneembodiment, the viewing element support portion 10898 has a generallykidney-shaped viewing window that can be positioned over the accessdevice 10896 and the viewing element 10892 can be positioned atlocations along the viewing window.

With reference to FIGS. 281-283, an access device mounting system 10900is provided with a simplified mount control arm 10902 for coupling withan access device 10904. In the illustrated embodiment, a distal portion10906 of the mount control arm 10902 is coupled with a proximal portion10908 of the access device 10904. The handle portion 10910 of the mountcontrol arm 10902 can be coupled with a vacuum pressure system similarto those described previously with respect to the mount control arms. Apressure release button 10912 can be configured on the mount control arm10902. The simplified structure for the mount control arm 10902 canprovide for increase visualization of the surgical location within theaccess device 10904 and can minimize the hardware associated withsupporting the access device 10904 in the desired position.

FIG. 284 is a perspective view of a surgical assembly 10920 having athumb-wheel lock and/or a cam lever lock. One embodiment of an accessdevice support assembly 10922 comprises an access device 10924 with aproximal portion 10926 and an expandable distal portion 10928. Asimplified access device mounting fixture 10930 comprises a yokeadjustment. In one embodiment, the access device mounting fixture 10930can comprise a thumb-wheel lock 10932. In another embodiment, the accessdevice mounting fixture 10930 can comprise a cam lever lock 10934. Themounting fixture 10930 preferably comprises a vacuum release button10934 in some embodiments.

The various devices, methods and techniques described above provide anumber of ways to carry out the invention. Of course, it is to beunderstood that not necessarily all objectives or advantages describedmay be achieved in accordance with any particular embodiment describedherein. Also, although the invention has been disclosed in the contextof certain embodiments and examples, it will be understood by thoseskilled in the art that the invention extends beyond the specificallydisclosed embodiments to other alternative embodiments and/or uses andobvious modifications and equivalents thereof. Accordingly, theinvention is not intended to be limited by the specific disclosures ofpreferred embodiments herein.

Many of the systems, apparatuses, methods, and features described hereincan be combined with many of the systems, apparatuses, methods andfeatures disclosed in the following patents and patent applications. Theentire disclosure of all of the following patents and patentapplications is hereby incorporated by reference herein and made a partof this specification: U.S. Pat. Nos. 6,361,488 (issued Mar. 26, 2002),6,530,880 (issued Mar. 11, 2003), 6,648,888 (issued Nov. 18, 2003),6,652,553 (issued Nov. 25, 2003), 6,641,583 (issued Nov. 4, 2003),6,554,832 (issued Apr. 29, 2003), 6,673,074 (issued Jan. 6, 2004), U.S.patent application Ser. Nos. 09/821,666 (filed Mar. 29, 2001, publishedOct. 3, 2002 as Publication No. U.S. 2002/0143328A1), 09/824,411 (filedApr. 2, 2001, published Oct. 3, 2002 as Publication No. U.S.2002/0143330A1), 09/921,326 (filed Aug. 2, 2001, published Feb. 6, 2003as Publication No. U.S. 2003/0028191A1), 09/940,402 (filed Aug. 27,2001, published Feb. 27, 2003 as Publication No. US 2003/0040656A1),10/075,668 (filed Feb. 13, 2002, published Aug. 14, 2003 as PublicationNo. U.S. 2003/0153911A1), 10/087,489 (filed Mar. 1, 2002, published Sep.4, 2003 as Publication No. U.S. 2003/0167058A1), 10/178,875 (filed Jun.24, 2002, published Dec. 25, 2003 as Publication No. U.S.2003/0236529A1), 10/280,489 (filed Oct. 25, 2002, published Apr. 17,2003 as Publication No. US 2003/0073998A1), 10/280,799 (filed Oct. 25,2002), Ser. No. 10/361,887 (filed Feb. 10, 2003, published Aug. 14, 2003as Publication No. US 2003/0153927A1), 10/658,736 (filed Sep. 9, 2003),10/678,744 (filed Oct. 2, 2003), 10/693,815 (filed Oct. 24, 2003),10/693,250 (filed Oct. 24, 2003), 10/693,663 (filed Oct. 24, 2003),10/842,651 (filed May 10, 2004), 10/845,389 (filed May 13, 2004) U.S.Provisional Applications No. 60/471,431 (filed May 16, 2003), 60/497,763(filed Aug. 26, 2003), 60/497,822 (filed Aug. 26, 2003), 60/513,796(filed Oct. 22, 2003), 60/513,013 (filed Oct. 23, 2003), 60/514,559(filed Oct. 24, 2003), 60/545,587 (filed Feb. 18, 2004), 60/558,296(filed Mar. 31, 2004), 60/579,643 (filed Jun. 15, 2004).

1. A device for retracting tissue to provide access to a spinal locationwithin a patient, said device comprising: a proximal portion partiallydefining a first portion of a path through which surgical instrumentscan be inserted to the surgical location; a distal portion partiallydefining a second portion of the path; a first joint located on a firstside of the device; and a second joint located on a second side of thedevice opposite the first joint; a gimbal ring, wherein the first andsecond joints are pivot joints; wherein said proximal portion definingthe first portion of the path is capable of being moved relative to saiddistal portion about a first axis extending through the first and secondjoints and about a second axis that is perpendicular to the first axis.2. The device of claim 1, wherein the gimbal ring comprises a first pairof apertures on opposite sides thereof through which a first pivot axisextends and a second pair of apertures located on opposite sides thereofthrough which a second pivot axis extends, the first pivot axis beingperpendicular to the second pivot axis.
 3. The device of claim 2,wherein a first pair of joints are formed at the first pair of aperturesand a second pair of joints are formed at the second pair of apertures,each of the first pair of joints comprising a member about which atleast one of the gimbal ring and the proximal portion can rotate, eachof the second pair of joints comprising a member about which at leastone of the gimbal ring and the distal portion can rotate.
 4. The deviceof claim 1, wherein the first and second joints are formed in part bythe distal portion and further comprising a third joint partially formedby the proximal portion.
 5. The device of claim 1, further comprising afourth joint coupled with the proximal portion, the third and fourthjoints being on opposite sides of the device, wherein the second axisextends through the third and fourth joints.
 6. The device of claim 1,wherein the first portion of the path has a first longitudinal axis andthe second portion of the path has a second longitudinal axis, whereinthe proximal portion is configured to be moved relative to the distalportion such that the first and second longitudinal axes are notcoaxial.